Top 100 Most Important Physics GK Questions for RRB Exams
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Are you preparing for RRB exams like RRB ALP, RRB Technician, or RRB NTPC?
Physics is a crucial subject that can significantly influence your
performance.
To help you practice the Physics section, we've compiled the Top 100 Most
Important Physics GK Questions frequently asked in various RRB exams. This
post will not only provide you with essential questions but also offer
valuable insights into the key topics and effective preparation strategies.
Most Asked Physics Topics for RRB Exams
Focusing on the right topics can streamline your preparation and maximize your
efficiency. Below is a table highlighting the
Most Asked Physics Topics in RRB exams, along with the number
of questions (in top 100 questions) typically associated with each topic.
Q1: If the forefinger indicates the direction of the magnetic field and the
thumb shows the direction of motion of a conductor, then the middle finger
will show the direction of induced current when the thumb, forefinger, and
middle finger are stretched perpendicular to each other. This is called ______
.
A. Fleming’s Left Hand Rule
B. Faraday’s Law
C. Fleming’s Right Hand Rule
D. Lenz’s Law
Fleming’s Right Hand Rule is used to determine the direction of induced
current in a conductor moving within a magnetic field. Introduced by John
Ambrose Fleming, this rule is essential in understanding the operation of
electrical generators.
The right-hand rule helps visualize the relationship
between the magnetic field, motion, and induced current, ensuring accurate
prediction of current direction in various electromagnetic applications.
Q2: The audible range of sound for human beings extends from about:
A. 20 Hz to 20,000 Hz
B. 100 Hz to 10,000 Hz
C. 50 Hz to 25,000 Hz
D. 5 Hz to 15,000 Hz
The human ear can typically hear sounds ranging from 20 Hertz (Hz) to 20,000
Hertz (20 kHz). This range encompasses the frequencies of most everyday
sounds. Sounds below 20 Hz are known as infrasound, and those above 20,000 Hz
are called ultrasound, both of which are generally inaudible to humans.
Understanding the audible range is crucial in fields like acoustics, audio
engineering, and hearing health.
Q3: If a lens has a focal length of 25 cm, what will be the power of that
lens?
A. 0.04 D
B. 4 D
C. 2.5 D
D. 25 D
The power (P) of a lens is given by the formula \( P = \frac{1}{f} \), where
\( f \) is the focal length in meters. Converting 25 cm to meters gives 0.25
m. Thus, \( P = \frac{1}{0.25} = 4 \) diopters (D). Power is a measure of how
strongly a lens converges or diverges light. A positive power indicates a
converging (convex) lens, while a negative power indicates a diverging
(concave) lens.
Q4: The splitting up of white light into seven components as it enters a glass
prism is called:
A. Dispersion of Light
B. Refraction
C. Reflection
D. Diffraction
Dispersion of light refers to the process where white light separates into its
constituent colors (spectrum) when it passes through a medium like a glass
prism. This phenomenon occurs because different colors (wavelengths) of light
bend by different amounts due to varying refractive indices. Dispersion is
fundamental in understanding optical phenomena and is the principle behind
devices like prisms and rainbows.
Q5: If a person has difficulty in seeing distant objects clearly, what
condition is he suffering from and how can it be corrected?
A. Astigmatism, using cylindrical lens
B. Presbyopia, using bifocal lenses
C. Myopia, using concave lens
D. Hyperopia, using convex lens
Myopia, or nearsightedness, is a common vision condition where distant objects
appear blurry while close objects can be seen clearly. This occurs because the
eye focuses images in front of the retina. It can be corrected using concave
lenses, which diverge light rays before they enter the eye, effectively moving
the focal point back onto the retina. Myopia correction is essential for
improving visual clarity and overall quality of life.
Q6: Mechanical energy is the sum of:
A. Kinetic energy + Electrical energy
B. Potential energy + Thermal energy
C. Kinetic energy + Potential energy
D. Kinetic energy + Thermal energy
Mechanical energy is the sum of kinetic energy (energy of motion) and
potential energy (stored energy due to position). It is a fundamental concept
in physics that applies to various systems, from simple pendulums to complex
machinery. Conservation of mechanical energy is a key principle, stating that
in the absence of non-conservative forces, the total mechanical energy remains
constant.
Q7: When an object is placed at a distance of 60 cm from a concave lens of
focal length 30 cm, then the magnification of the image is:
A. +0.5
B. +0.33
C. -0.5
D. -0.33
For a lens, magnification \( m \) is given by \( m = \frac{v}{u} \), where \(
v \) is the image distance and \( u \) is the object distance. Using the lens
formula \( \frac{1}{f} = \frac{1}{v} - \frac{1}{u} \), and substituting \( f =
-30 \) cm (since it's a concave lens) and \( u = -60 \) cm, we find \( v = -20
\) cm. Thus, \( m = \frac{-20}{-60} = +0.33 \). The positive magnification
indicates that the image is virtual and upright.
Q10: The rate of doing work is called power. The unit of power is:
A. Joule (J)
B. Newton (N)
C. Watt (W)
D. Pascal (Pa)
Power is defined as the rate at which work is done or energy is transferred.
The SI unit of power is the watt (W), named after James Watt, a Scottish
inventor and mechanical engineer. One watt is equivalent to one joule per
second (1 W = 1 J/s). Power is a fundamental concept in both physics and
engineering, crucial for understanding energy consumption and machinery
efficiency.
Q11: 77 °F is equal to:
A. 0°C
B. 25°C
C. 50°C
D. 100°C
The conversion formula from Fahrenheit (°F) to Celsius (°C) is \( C =
\frac{5}{9}(F - 32) \). Applying this, \( C = \frac{5}{9}(77 - 32) =
\frac{5}{9}(45) = 25°C \). Understanding temperature conversion is essential
in various scientific calculations and everyday applications, especially in
international contexts where different temperature scales are used.
Q12: The radius of curvature of a concave mirror is 12 cm. Following New
Cartesian Sign Convention, the principal focus is located at x = ______.
A. +12 cm
B. -12 cm
C. -6 cm
D. +6 cm
For a concave mirror, the radius of curvature (R) is related to the focal
length (f) by \( R = 2f \). Given R = 12 cm, the focal length \( f =
\frac{R}{2} = 6 \) cm. According to the New Cartesian Sign Convention, the
focal length of a concave mirror is taken as negative. Therefore, the
principal focus is located at x = -6 cm. This convention helps in consistently
applying mirror and lens formulas in geometrical optics.
Q13: The color of the clear sky is blue due to ______ of light by particles in
the atmosphere of size ______ than the wavelength of visible light.
A. Absorption, similar
B. Scattering, smaller
C. Refraction, larger
D. Reflection, larger
The sky appears blue because of Rayleigh scattering, where particles in the
atmosphere scatter shorter (blue) wavelengths of sunlight more effectively
than longer (red) wavelengths. This scattering occurs when the particles are
smaller than the wavelength of visible light. As a result, blue light is
dispersed in all directions, making the sky look blue to observers on the
ground. This phenomenon was first explained by physicist Lord Rayleigh.
Q14: The filament of an electric bulb is made up of which of the given
materials?
A. Iron
B. Aluminum
C. Copper
D. Tungsten
Tungsten is used for the filament in incandescent light bulbs due to its high
melting point (3422°C) and good electrical conductivity. These properties
allow the filament to withstand high temperatures without melting, ensuring a
long-lasting light source. Tungsten's ability to emit light when heated
(incandescence) makes it ideal for this application. Its discovery and
application have been crucial in the development of electric lighting.
Q15: ______ is the SI unit of electric charge and is equivalent to the charge
contained in nearly 6 x 10^18 electrons.
A. Coulomb
B. Volt
C. Ohm
D. Ampere
The coulomb (C) is the SI unit of electric charge. One coulomb is
approximately equal to the charge of \( 6.242 \times 10^{18} \) electrons.
This unit is fundamental in the study of electricity and electromagnetism,
quantifying the amount of charge transported by a constant current of one
ampere in one second. Understanding the coulomb is essential for calculations
involving electric circuits, electrostatics, and charge interactions.
Q16: What is defined as the product of mass and velocity?
A. Momentum
B. Power
C. Force
D. Energy
Momentum is defined as the product of an object's mass (m) and its velocity
(v), expressed as \( p = mv \). It is a vector quantity, possessing both
magnitude and direction. Momentum is a fundamental concept in mechanics,
particularly in the study of collisions and interactions. The principle of
conservation of momentum states that in the absence of external forces, the
total momentum of a system remains constant. This principle is pivotal in
various applications, from vehicle safety design to astrophysics.
Q17: What is defined as the rate of doing work or the rate of transfer of
energy?
A. Force
B. Power
C. Work
D. Energy
Power is defined as the rate at which work is done or energy is transferred
over time. Mathematically, power \( P \) is given by \( P = \frac{W}{t} \),
where \( W \) is work and \( t \) is time. The SI unit of power is the watt
(W), which is equivalent to one joule per second. Power is a crucial concept
in various fields, including mechanics, thermodynamics, and electrical
engineering, as it quantifies how quickly energy is used or transformed.
Q18: A bulb draws a current of 3A when connected to a battery of 12V. The
power of the bulb is:
A. 4 W
B. 144 W
C. 12 W
D. 36 W
Power (\( P \)) consumed by an electrical device can be calculated using the
formula \( P = VI \), where \( V \) is the voltage and \( I \) is the current.
Substituting the given values: \( P = 12V \times 3A = 36W \). Power rating is
essential for determining the energy consumption and efficiency of electrical
appliances. Understanding this calculation helps in designing electrical
circuits and ensuring the safe operation of devices.
Q19: Which law or principle says that “when a body is immersed fully or
partially in a fluid, it experiences an upward force that is equal to the
weight of the fluid displaced by it”?
A. Archimedes' Principle
B. Newton's First Law
C. Bernoulli's Principle
D. Pascal's Law
Archimedes' Principle states that any object submerged in a fluid experiences
an upward buoyant force equal to the weight of the fluid it displaces. This
principle explains why objects float or sink in fluids and is fundamental in
the design of ships, submarines, and other floating structures. It was first
discovered by the ancient Greek scientist Archimedes while he was taking a
bath, leading to his famous exclamation, "Eureka!"
Q20: The number of complete oscillations per unit time is called the ______.
A. Wavelength
B. Amplitude
C. Period
D. Frequency
Frequency is defined as the number of complete oscillations or cycles that
occur per unit of time, typically measured in hertz (Hz). It is a fundamental
property of waves, including sound and electromagnetic waves. Higher frequency
means more oscillations per second, which affects the pitch of sound or the
color of light. Understanding frequency is essential in various applications,
from tuning musical instruments to designing wireless communication systems.
Q21: What is the repeated reflection of sound from the walls of a big hall
that results in persistence of sound called?
A. Reverberation
B. Echo
C. Diffraction
D. Resonance
Reverberation refers to the persistence of sound in an enclosed space after
the original sound is produced, caused by multiple reflections of sound waves
off surfaces like walls, ceilings, and floors. Unlike an echo, which is a
distinct repetition of sound after a delay, reverberation creates a prolonged,
blended sound. This phenomenon is important in acoustical engineering for
designing auditoriums, concert halls, and recording studios to achieve desired
sound qualities.
Q22: The center of the reflecting surface of a spherical mirror is a point
called:
A. Vertex
B. Focus
C. Pole
D. Center of Curvature
The pole of a spherical mirror is the geometric center of the reflecting
surface. It is the point where the principal axis intersects the mirror's
surface. Understanding the pole is essential when applying mirror formulas and
analyzing image formation in geometrical optics. The center of curvature,
another key point, is the center of the sphere from which the mirror is a
part, and it lies along the principal axis.
Q23: Which type of mirror is used by dentists to see large images of patients’
teeth?
A. Convex Mirror
B. Plane Mirror
C. Concave Mirror
D. Spherical Mirror
Dentists use concave mirrors to view larger and magnified images of patients’
teeth. The concave shape allows the mirror to focus light and provide a
magnified, clear image, enhancing visibility in the confined space of the
mouth. This application of concave mirrors is a practical example of how
geometrical optics is utilized in medical instruments to improve diagnostic
capabilities.
Q24: An object of size 1.0 cm is placed in front of a concave mirror of focal
length 16 cm, at a distance of 24 cm. The image formed is ______ and its
height is ______.
A. Inverted, 2.0 cm
B. Virtual, 1.5 cm
C. Real, 1.0 cm
D. Upright, 0.66 cm
Using the mirror formula \( \frac{1}{f} = \frac{1}{u} + \frac{1}{v} \), where
\( f = -16 \) cm (concave mirror), and \( u = -24 \) cm, we find \( v = -48 \)
cm. The magnification \( m = \frac{v}{u} = \frac{-48}{-24} = 2 \). Thus, the
image is inverted and twice the size of the object, making the height 2.0 cm.
The negative image distance indicates a real image formed on the same side as
the object.
Q25: If the power of a convex lens is 3 dioptre, then its focal length will
be:
A. +0.33 m
B. -0.33 m
C. +3 m
D. -3 m
The power \( P \) of a lens is given by \( P = \frac{1}{f} \), where \( f \)
is the focal length in meters. For a convex lens, the power is positive. Given
\( P = 3 \) diopters, the focal length \( f = \frac{1}{3} \approx 0.33 \)
meters. Convex lenses converge light rays and are used in applications like
magnifying glasses and corrective lenses for hyperopia (farsightedness).
Q26: Which color among the seven colors of white light gets least deviated
after dispersion of light through a glass prism?
A. Orange
B. Blue
C. Violet
D. Red
Red light is least deviated when white light disperses through a glass prism
because it has the longest wavelength among the visible colors. Dispersion
occurs due to the dependence of the refractive index on wavelength, with
shorter wavelengths (like violet) bending more than longer wavelengths (like
red). This phenomenon explains the order of colors in a rainbow and the
separation of light into its constituent colors by a prism.
Q27: Among various electrical safety devices, one based on the heating effect
of electric current is called a ______.
A. Surge Protector
B. Fuse
C. Circuit Breaker
D. Residual Current Device
A fuse is an electrical safety device that protects circuits by melting and
breaking the circuit when excessive current flows through it, based on the
heating effect of electric current. When the current exceeds the fuse's rated
capacity, the heat generated causes the fuse wire to melt, interrupting the
current flow and preventing potential damage or fire. Fuses are simple,
cost-effective, and widely used in household and industrial electrical
systems.
Q28: The strength of the magnetic field inside a long current-carrying
straight solenoid is:
A. Non-uniform
B. Stronger at the ends
C. Uniform at all points inside the solenoid
D. Zero
The magnetic field inside a long, tightly wound, current-carrying solenoid is
uniform and parallel at all points inside the solenoid. This uniformity is due
to the additive effect of the magnetic fields generated by each turn of the
coil. The field outside a long solenoid is negligible. The strength of the
magnetic field inside the solenoid is given by \( B = \mu_0 n I \), where \(
\mu_0 \) is the permeability of free space, \( n \) is the number of turns per
unit length, and \( I \) is the current.
Q29: What is the standard unit for luminous intensity?
A. Lux
B. Candela
C. Watt
D. Lumen
The candela (cd) is the SI unit of luminous intensity, which measures the
perceived power of light by the human eye in a particular direction. It is one
of the seven base units in the International System of Units (SI). The candela
is essential in photometry, the science of measuring visible light, and is
used to quantify the brightness of light sources like lamps and LEDs.
Understanding luminous intensity is crucial for lighting design and evaluating
visual ergonomics.
Q30: Noise pollution is measured in terms of ______.
A. Watt
B. Pascal
C. Hertz
D. Decibel
Noise pollution is quantified using the decibel (dB) scale, which measures the
intensity of sound. The decibel scale is logarithmic, meaning that each
increase of 10 dB represents a tenfold increase in sound intensity. For
example, normal conversation typically occurs around 60 dB, while a loud rock
concert can reach 120 dB. Monitoring noise levels is important for public
health, environmental regulations, and urban planning to minimize adverse
effects on human well-being.
Q31: The SI unit of power of a lens is:
A. Joule
B. Dioptre
C. Watt
D. Newton
The power of a lens is measured in dioptres (D), which is the SI unit for
optical power. One dioptre is equal to the reciprocal of the focal length in
meters (\( D = \frac{1}{f} \)). For example, a lens with a focal length of 0.5
meters has a power of 2 dioptres. Dioptres are used to describe the refractive
power of lenses in eyeglasses, cameras, and other optical instruments,
indicating how strongly the lens converges or diverges light.
The pascal (Pa) is the SI unit of pressure, defined as one newton per square
meter (1 Pa = 1 N/m²). Pressure quantifies the force applied perpendicular to
the surface of an object per unit area over which that force is distributed.
It is a fundamental concept in various fields, including fluid mechanics,
meteorology, and engineering. Common applications include atmospheric pressure
measurement, tire pressure monitoring, and hydraulic systems.
Q34: What is the commercial unit of electrical energy consumed?
A. Ampere hour (Ah)
B. Kilowatt hour (kWh)
C. Watt (W)
D. Joule (J)
The kilowatt hour (kWh) is the commercial unit used to measure electrical
energy consumption. One kWh is equal to the energy consumed by a 1,000-watt
device running for one hour. Utility companies use kWh to bill customers for
their electricity usage. Understanding kWh is important for managing energy
consumption, calculating electricity costs, and implementing energy-saving
measures in households and industries.
Q35: What is the unit of measurement of very long distances between celestial
bodies?
A. Astronomical Unit
B. Light year
C. Parsec
D. Kilometer
A light year is the unit of measurement used to express very long distances in
space, representing the distance that light travels in one year, approximately
\( 9.46 \times 10^{12} \) kilometers. It is commonly used in astronomy to
describe distances between stars, galaxies, and other celestial objects.
Understanding light years is essential for comprehending the vast scales of
the universe and the time it takes for light to traverse these immense
distances.
Q36: Which device is used to measure the atmospheric pressure?
A. Anemometer
B. Hygrometer
C. Barometer
D. Thermometer
A barometer is an instrument used to measure atmospheric pressure. There are
two main types of barometers: mercury barometers and aneroid barometers.
Mercury barometers use a column of mercury to measure pressure changes, while
aneroid barometers use a sealed, flexible metal chamber that expands or
contracts with pressure changes. Measuring atmospheric pressure is crucial for
weather forecasting, aviation, and understanding meteorological phenomena.
Q37: Which instrument is used to detect whether an object is a charge carrier
or not?
A. Voltmeter
B. Ammeter
C. Galvanometer
D. Electroscope
An electroscope is an instrument used to detect the presence and magnitude of
electric charge on a body. It consists of a metal rod connected to two thin
metal leaves, which diverge when charged due to electrostatic repulsion.
Electroscopes can indicate whether an object is a conductor (charge carrier)
or an insulator by observing the behavior of the leaves when the object is
brought near. This device is fundamental in studying static electricity and
charge distribution.
Q38: An electric generator is a device which converts:
A. Chemical energy into electrical energy
B. Electrical energy into mechanical energy
C. Mechanical energy into electrical energy
D. Thermal energy into electrical energy
An electric generator converts mechanical energy into electrical energy
through electromagnetic induction. When a conductor, such as a coil of wire,
moves within a magnetic field, an electric current is induced in the
conductor. This principle is the basis for generating electricity in power
plants, where mechanical energy from turbines (driven by steam, water, or
wind) is converted into electrical power for distribution and use. Generators
are essential components in the global energy infrastructure.
Q39: The tendency of undisturbed objects to stay at rest or to keep moving
with the same velocity is called ______.
A. Force
B. Inertia
C. Momentum
D. Acceleration
Inertia is the property of matter that causes it to resist changes in its
state of motion. An object at rest will remain at rest, and an object in
motion will continue moving at a constant velocity unless acted upon by an
external force. This principle is Newton's First Law of Motion. Inertia
depends on an object's mass; the greater the mass, the greater the inertia.
Understanding inertia is fundamental in analyzing motion and the effects of
forces on objects.
Q40: What is the principle on which a rocket works?
A. Newton's First Law
B. Conservation of Energy
C. Newton's Second Law
D. Newton's Third Law
Rockets operate based on Newton's Third Law of Motion, which states that for
every action, there is an equal and opposite reaction. In a rocket, the
expulsion of exhaust gases downward creates an upward thrust that propels the
rocket forward. This principle is fundamental in aerospace engineering and is
critical for launching spacecraft, satellites, and other vehicles into space.
Understanding action and reaction forces is essential for designing efficient
propulsion systems.
Q41: ______ is defined as the total path length travelled by an object divided
by the total time interval during which the motion has taken place.
A. Displacement
B. Velocity
C. Acceleration
D. Speed
Speed is a scalar quantity defined as the total distance traveled divided by
the total time taken. It does not have a direction, unlike velocity, which is
a vector. Speed is commonly measured in units like meters per second (m/s) or
kilometers per hour (km/h). It is a fundamental concept in kinematics, used to
describe how fast an object is moving regardless of its direction of motion.
Q42: The change in velocity of an object per unit time is called ______.
A. Acceleration
B. Speed
C. Momentum
D. Force
Acceleration is a vector quantity defined as the rate of change of velocity
with respect to time. It can represent an increase or decrease in speed or a
change in direction. The SI unit of acceleration is meters per second squared
(m/s²). Acceleration is a key concept in dynamics, relating to how forces
affect the motion of objects according to Newton's Second Law (\( F = ma \)).
Q43: What is the frictional force exerted by the fluids also called?
A. Lift
B. Drag
C. Thrust
D. Buoyancy
Drag is the frictional force exerted by fluids (liquids or gases) opposing the
motion of an object moving through them. It acts in the direction opposite to
the object's velocity and depends on factors like the object's speed, shape,
size, and the fluid's viscosity. Understanding drag is essential in fields
like aerodynamics, automotive engineering, and sports science to design
objects that move efficiently through fluids.
Q44: An object of mass 15 kg is moving with a uniform velocity of 4 m/s. What
is the kinetic energy possessed by the object?
A. 30 J
B. 60 J
C. 240 J
D. 120 J
Kinetic energy (\( Ek \)) is given by the formula \( Ek = \frac{1}{2}mv^2 \),
where \( m \) is mass and \( v \) is velocity. Substituting the given values:
\( Ek = \frac{1}{2} \times 15 \times (4)^2 = \frac{1}{2} \times 15 \times 16 =
120 \) joules. Kinetic energy is a measure of the energy an object possesses
due to its motion and is essential in mechanics and energy conservation
studies.
Q45: The rate at which electric work is done or the rate at which electrical
energy is consumed is called ______.
A. Current
B. Voltage
C. Power
D. Resistance
Power in an electrical context is defined as the rate at which electric work
is done or electrical energy is consumed. It is calculated using the formula
\( P = VI \), where \( V \) is voltage and \( I \) is current. The SI unit of
power is the watt (W). Power ratings are crucial for determining the energy
consumption of electrical devices and ensuring that circuits are designed to
handle the required load without overheating or failure.
Q46: One horse-power (hp) 1 hp = ______ W.
A. 746
B. 1200
C. 550
D. 1000
One horse-power is equivalent to approximately 746 watts. The horsepower unit
was originally defined to compare the output of steam engines with the power
of draft horses. Today, it is still commonly used to describe the power output
of engines, motors, and other mechanical devices. Understanding horsepower and
its conversion to watts is important in engineering, automotive industries,
and energy calculations.
Q47: The loudness or softness of a sound is basically determined by its:
A. Velocity
B. Amplitude
C. Wavelength
D. Frequency
The loudness of a sound is determined by its amplitude, which is the maximum
displacement of the particles in the medium through which the sound is
traveling. Greater amplitude means higher energy and louder sound, while
smaller amplitude results in softer sound. Amplitude is measured in units such
as decibels (dB). Loudness perception is also influenced by the frequency of
the sound, but amplitude is the primary factor.
Q48: Sound of single frequency is called ______.
A. Resonance
B. Noise
C. Tone
D. Echo
A sound consisting of a single frequency is called a tone. Tones are pure
sounds with a clear pitch and no harmonic overtones. They are fundamental in
music and acoustics, where different frequencies correspond to different
musical notes. In contrast, noise consists of multiple frequencies and lacks a
distinct pitch. Understanding tones is essential in fields like audio
engineering, music theory, and speech processing.
Q49: In a longitudinal wave, the distance between two consecutive compressions
and two consecutive rarefactions is called:
A. Frequency
B. Wavelength
C. Amplitude
D. Velocity
Wavelength is the distance between two consecutive compressions or two
consecutive rarefactions in a longitudinal wave. It is a key parameter in
characterizing waves, alongside frequency and velocity. Wavelength is
typically measured in meters and is inversely related to frequency for a given
wave speed. Understanding wavelength is essential in acoustics, optics, and
various applications involving wave phenomena.
Q50: Sound CANNOT travel through :
A. Solids
B. Water
C. Vacuum
D. Air
Sound requires a medium (solid, liquid, or gas) to propagate because it
travels as a mechanical wave through the vibration of particles. In a vacuum,
where there are no particles to vibrate, sound cannot travel. This is why
space is silent despite being filled with celestial objects and phenomena.
Understanding the dependence of sound on a medium is fundamental in acoustics
and space exploration.
Q51: What is the expansion of “SONAR”?
A. Sound Navigation and Ranging
B. Sound Observation and Navigation and Ranging
C. Sound Oscillation and Navigation and Ranging
D. Sonar Navigation and Ranging
SONAR stands for Sound Navigation and Ranging. It is a technique that uses
sound waves to detect and locate objects underwater, such as submarines,
ships, and marine life. SONAR systems emit sound pulses and listen for their
echoes, measuring the time taken for the echoes to return to determine the
distance to the object. This technology is crucial in naval operations,
underwater exploration, and marine biology.
Q52: -100° Celsius = ______ Fahrenheit
A. -200°
B. -40°
C. -148°
D. -100°
The conversion formula from Celsius (°C) to Fahrenheit (°F) is \( F =
\frac{9}{5}C + 32 \). Substituting \( C = -100 \): \( F = \frac{9}{5}(-100) +
32 = -180 + 32 = -148° \). Accurate temperature conversion is important in
scientific calculations, engineering, and everyday applications where
different temperature scales are used.
Q53: What is the distance of the principal focus F from the pole P of the
spherical mirror called?
A. Focal length (f)
B. Image distance
C. Object distance
D. Radius of curvature
The focal length (\( f \)) of a spherical mirror is the distance between the
principal focus (F) and the pole (P) of the mirror. For concave mirrors, the
focal length is positive, while for convex mirrors, it is negative, following
the sign conventions. The focal length is half the radius of curvature (\( R
\)), so \( f = \frac{R}{2} \). Understanding focal length is crucial for image
formation and optical system design.
Q54: The distance between the focus and the center of curvature of a spherical
mirror in terms of the radius of curvature R, is equal to:
A. R
B. \( 2R \)
C. \( \frac{R}{2} \)
D. \( \frac{R}{4} \)
The focal length (\( f \)) of a spherical mirror is half the radius of
curvature (\( R \)), so \( f = \frac{R}{2} \). This relationship is derived
from the geometry of spherical mirrors and is fundamental in geometrical
optics. Knowing this relation helps in determining the image distance and
magnification when using mirror formulas.
Q55: An object must be placed ______ to obtain a real and inverted image of
the same size as that of the object after reflection.
A. At F of a concave mirror
B. Beyond C of a concave mirror
C. At C of a concave mirror
D. Between F and P of a concave mirror
When an object is placed at the center of curvature (C) of a concave mirror,
the image formed is real, inverted, and of the same size as the object. This
occurs because the object and image are equidistant from the mirror's pole.
The center of curvature is located at a distance equal to the radius of
curvature from the mirror's surface. Understanding this positioning is
essential for image formation studies in geometrical optics.
Q56: Which kind of mirrors is used as rear-view wing mirrors in vehicles?
A. Convex mirrors
B. Concave mirrors
C. Plane mirrors
D. Spherical mirrors
Convex mirrors are used as rear-view wing mirrors in vehicles because they
provide a wider field of view compared to plane mirrors. This curvature causes
light rays to diverge, allowing drivers to see more area behind and beside the
vehicle, enhancing safety by reducing blind spots. Although images formed by
convex mirrors are smaller and virtual, their ability to offer a broader
perspective is highly beneficial in automotive applications.
Q57: When a light ray enters from a denser medium to a rarer medium, say from
glass to air, how does the light ray bend?
A. Parallel to the surface
B. Away from the normal
C. Towards the normal
D. Does not bend
When light travels from a denser medium (like glass) to a rarer medium (like
air), it bends away from the normal due to a decrease in the speed of light in
the denser medium. This bending is described by Snell's Law, \( n_1 \sin
\theta_1 = n_2 \sin \theta_2 \), where \( n \) represents the refractive
index. Understanding refraction is essential in optics, affecting lens design,
vision correction, and the behavior of light in different materials.
Q58: Which set of sign conventions is followed while dealing with reflection
of light by spherical mirrors?
A. Cartesian sign convention
B. New Cartesian sign convention
C. Polar sign convention
D. None of the above
The New Cartesian sign convention is used for spherical mirrors, where
distances measured against the direction of incoming light are taken as
negative, and those measured in the direction of incoming light are positive.
For mirrors, the focal length is negative for concave mirrors and positive for
convex mirrors. This convention ensures consistency in applying mirror
formulas and calculating image properties. Understanding sign conventions is
crucial for accurate geometrical optics calculations.
Q59: Twinkling of stars at night happens due to ______.
A. Atmospheric refraction
B. Dispersion
C. Reflection
D. Absorption
The twinkling of stars, also known as stellar scintillation, occurs due to
atmospheric refraction. As starlight passes through Earth's turbulent
atmosphere, variations in air density and temperature cause the light to bend
unpredictably, making the star appear to twinkle. This effect is more
pronounced for stars near the horizon where light travels through more
atmospheric layers. Understanding this phenomenon is important in astronomy
for improving the accuracy of telescopic observations.
Q60: It is found that during dispersion of white light by a glass prism, the
more a color component is bent, the more is the refractive index of the glass
for that color component. If µY, µR, µB, µV and µG are refractive indices for
yellow, red, blue, violet and green lights, respectively, then which relation
between them is correct?
A. µB > µG > µV > µY > µR
B. µR > µY > µG > µB > µV
C. µG > µV > µB > µY > µR
D. µV > µB > µG > µY > µR
During dispersion, colors with shorter wavelengths (like violet and blue) are
bent more and thus have higher refractive indices in glass, while colors with
longer wavelengths (like red) are bent less and have lower refractive indices.
The correct order is µV > µB > µG > µY > µR. This order explains why violet
light is seen at one end of the spectrum and red light at the other when white
light passes through a prism. Understanding dispersion is essential in optics
and the study of light behavior.
Q61: When a photograph of Earth is taken from space its background looks dark
because of:
A. No scattering of light
B. No scattering of light
C. No reflection of light
D. Absorption of light
In space, there is a vacuum with no atmosphere to scatter light. As a result,
the background appears dark because light is not being scattered by particles,
unlike on Earth where atmospheric scattering makes the sky appear blue.
Without scattering, only direct light from objects is visible, and the vast
expanse between celestial bodies remains dark. This absence of scattered light
is why space photographs show stark contrasts between illuminated objects and
the surrounding darkness.
Q62: What would be the color of the sky as viewed by an astronaut at the
International Space Station?
A. Blue
B. Gray
C. White
D. Black
From the International Space Station (ISS), astronauts observe that the sky
appears black. This is because there is no atmospheric scattering of sunlight
in space, which on Earth causes the sky to appear blue. In the vacuum of
space, without an atmosphere, light travels unimpeded, resulting in a dark
backdrop against which celestial objects are clearly visible. This observation
is a direct consequence of the absence of atmospheric particles to scatter
light.
Q63: Which color among the seven colors of the white light gets most deviated
after dispersion of light through a glass prism?
A. Blue
B. Violet
C. Red
D. Orange
Violet light has the shortest wavelength among the visible spectrum colors and
is thus deviated the most when white light disperses through a glass prism.
This greater deviation occurs because violet light experiences a higher
refractive index compared to other colors, causing it to bend more. This
property is essential in the formation of rainbows and the separation of light
into its constituent colors.
Q64: The mathematical form of Ohm’s law is represented as ______. (Here V =
potential difference, I = current flowing through a conductor and R =
Resistance.)
A. I = V/R
B. V = IR
C. R = VI
D. I = VR
Ohm’s Law states that the current (\( I \)) flowing through a conductor
between two points is directly proportional to the voltage (\( V \)) across
the two points and inversely proportional to the resistance (\( R \)) of the
conductor. The mathematical form is \( I = \frac{V}{R} \). This fundamental
law is essential for analyzing electrical circuits, determining component
values, and understanding the relationship between voltage, current, and
resistance in various applications.
Q65: Fleming’s right hand rule gives the direction of current induced in a
conductor moving in a ______.
A. Gravitational field
B. Magnetic field
C. Electric field
D. None of the above
Fleming’s Right Hand Rule is used to determine the direction of induced
current when a conductor moves within a magnetic field. The rule states that
if the thumb, forefinger, and middle finger are stretched perpendicular to
each other, with the forefinger pointing in the direction of the magnetic
field and the thumb in the direction of motion, the middle finger will point
in the direction of the induced current. This principle is fundamental in the
operation of electrical generators and understanding electromagnetic
induction.
Q66: What are the two most common materials used to make wires for electricity
transmission?
A. Iron and steel
B. Silver and gold
C. Copper and aluminum
D. Nickel and titanium
Copper and aluminum are the two most commonly used materials for electrical
transmission wires. Copper is favored for its excellent electrical
conductivity, ductility, and reliability, making it ideal for residential and
industrial wiring. Aluminum, being lighter and less expensive than copper, is
often used in high-voltage transmission lines. Both materials have good
conductivity-to-weight ratios and are essential in the efficient distribution
of electrical power across vast distances.
Q67: Source of voltage V maintains a current I in a circuit. The power (P)
input to the circuit by the source is given by:
A. \( P = V - I \)
B. \( P = V \times I \)
C. \( P = \frac{V}{I} \)
D. \( P = V + I \)
The power (\( P \)) supplied by a voltage source is calculated using the
formula \( P = VI \), where \( V \) is the voltage and \( I \) is the current.
This relationship indicates that power increases with both higher voltage and
higher current. Understanding this formula is crucial for designing and
analyzing electrical circuits, ensuring components can handle the required
power without overheating or failing.
Q68: A source maintains a current I in a resistor of resistance R. If V is the
potential difference across the resistor, the electrical energy dissipated in
the resistor in time t is given by ______.
A. \( VI + t \)
B. \( VIt \)
C. \( V + It \)
D. \( \frac{V}{I} t \)
The electrical energy (\( E \)) dissipated in a resistor over time (\( t \))
is given by \( E = VIt \), where \( V \) is the potential difference and \( I
\) is the current. This formula combines power (\( P = VI \)) with time to
calculate energy (\( E = Pt \)). It is essential for determining energy
consumption in electrical devices and for designing circuits to ensure
components can handle the required energy without damage.
Q71: The magnetic field lines inside the solenoid are in the form of ______.
A. Circular loops
B. Diverging lines
C. Converging lines
D. Parallel straight lines
Inside a long, current-carrying solenoid, the magnetic field lines are
parallel and straight, running uniformly along the length of the solenoid.
This uniform field is due to the additive effect of the magnetic fields from
each turn of the coil. Outside the solenoid, the field lines spread out and
loop back around. The uniform internal magnetic field is crucial for
applications like electromagnets, inductors, and magnetic resonance imaging
(MRI).
Q72: Which is the main fuel used in a nuclear power plant?
A. Plutonium-239
B. Coal
C. Uranium-235
D. Natural Gas
Uranium-235 is the primary fuel used in most nuclear power plants. It
undergoes nuclear fission, releasing a significant amount of energy used to
generate electricity. Uranium-235 is preferred due to its ability to sustain a
nuclear chain reaction. While Plutonium-239 is also used in some reactors and
nuclear weapons, Uranium-235 remains the most common fuel in commercial
nuclear energy production. Understanding nuclear fuel is essential in the
study of nuclear physics and energy production.
Q73: The SI unit of heat energy transferred is expressed in ______.
A. British Thermal Unit (BTU)
B. Joule
C. Watt-hour
D. Calorie
The joule (J) is the SI unit of energy, including heat energy transferred. One
joule is equivalent to the energy transferred when applying a force of one
newton over a distance of one meter. Joules are used universally in scientific
calculations involving energy, work, and heat, providing a standard measure
for comparing different energy forms and processes. Understanding energy units
is fundamental in thermodynamics, chemistry, and engineering disciplines.
Q74: What is the SI unit of force?
A. Newton
B. Pascal
C. Joule
D. Watt
The newton (N) is the SI unit of force. It is defined as the force required to
accelerate a one-kilogram mass by one meter per second squared (\( 1 \,
\text{N} = 1 \, \text{kg} \cdot \text{m/s}^2 \)). Named after Sir Isaac
Newton, the unit is fundamental in mechanics, used to quantify forces in
various applications, from everyday objects to complex engineering systems.
Understanding force units is essential for analyzing motion, equilibrium, and
dynamics.
Q75: What is the SI unit of weight?
A. Kilogram
B. Joule
C. Pascal
D. Newton
Weight is a measure of the force exerted on an object due to gravity. Its SI
unit is the newton (N), the same as the unit for force. Weight is calculated
by multiplying an object's mass (\( m \)) by the acceleration due to gravity
(\( g \)), \( W = mg \). Unlike mass, which is a scalar quantity measured in
kilograms (kg), weight is a vector quantity with direction, making the newton
the appropriate unit. Understanding weight is crucial in fields like physics,
engineering, and biomechanics.
Q76: The SI unit of potential difference is ______.
The volt (V) is the SI unit of electric potential difference, also known as
voltage. One volt is defined as the potential difference that would move one
ampere of current against one ohm of resistance (\( V = IR \)). Named after
Alessandro Volta, a pioneer in electricity, the volt is fundamental in
electrical engineering, circuit analysis, and power distribution.
Understanding voltage is essential for designing and operating electrical
systems safely and efficiently.
Q77: The SI unit of “Magnetic flux” is:
A. Henry (H)
B. Weber (Wb)
C. Gauss (G)
D. Tesla (T)
The weber (Wb) is the SI unit of magnetic flux, representing the total
magnetic field passing through a given area. One weber is equivalent to one
tesla meter squared (\( 1 \, \text{Wb} = 1 \, \text{T} \cdot \text{m}^2 \)).
Magnetic flux is a key concept in electromagnetism, used in Faraday's Law of
Induction and the operation of devices like transformers and inductors.
Understanding magnetic flux is essential for analyzing and designing
electrical and magnetic systems.
Q78: Which quantity is expressed in kilograms per cubic meter (Kg/m³)?
A. Velocity
B. Force
C. Pressure
D. Density
Density is defined as mass per unit volume and is expressed in kilograms per
cubic meter (kg/m³) in the SI system. It quantifies how much mass is contained
in a given volume of a substance. Density is a fundamental property used in
various scientific and engineering disciplines, including material science,
fluid mechanics, and chemistry. Understanding density helps in identifying
substances, predicting buoyancy, and designing structures.
Q79: According to the International System (SI), the units of amplitude are
______.
A. Second (s)
B. Meter (m)
C. Newton (N)
D. Joule (J)
Amplitude, in the context of waves, refers to the maximum displacement of
points on a wave from their equilibrium position. Its SI unit is the meter
(m), representing the distance of this displacement. Amplitude is a
fundamental property of waves, affecting characteristics like intensity and
energy. Understanding amplitude is essential in fields like acoustics, optics,
and electromagnetic wave theory.
Q80: The SI number of electrical conductance is ______.
Siemens (S) is the SI unit of electrical conductance, which quantifies how
easily electricity flows through a material. Conductance is the reciprocal of
resistance (\( G = \frac{1}{R} \)), and one siemens is equal to one reciprocal
ohm (\( 1 \, \text{S} = 1/\Omega \)). Named after Ernst Werner von Siemens,
the unit is essential in electrical engineering and circuit analysis for
designing and understanding conductive pathways and components.
Q81: Which of the following have the same unit, m/s? 1) Velocity and
acceleration 2) Acceleration and momentum 3) Speed and momentum 4) Speed and
velocity
A. 1 and 4
B. 1 only
C. 2 only
D. 4 only
Both speed and velocity have the same unit, meters per second (m/s). Speed is
a scalar quantity representing how fast an object is moving, while velocity is
a vector quantity that includes both speed and direction. Acceleration has
units of meters per second squared (m/s²), and momentum has units of kilogram
meters per second (kg·m/s). Therefore, only speed and velocity share the same
unit.
Q82: Which circuit is used for measuring irregular resistance?
A. Wheatstone Bridge
B. RLC Circuit
C. Series Circuit
D. Parallel Circuit
The Wheatstone Bridge is an electrical circuit used to precisely measure
unknown resistances by balancing two legs of a bridge circuit. It consists of
four resistors arranged in a diamond shape, with a voltage source and a
galvanometer. When the bridge is balanced, the ratio of two resistances equals
the ratio of the other two, allowing the unknown resistance to be calculated
accurately. This method is fundamental in laboratory measurements and
instrumentation.
Q83: Name the world-famous scientist known for his theory of relativity.
A. Nikola Tesla
B. Isaac Newton
C. Galileo Galilei
D. Albert Einstein
Albert Einstein is the renowned scientist known for developing the theory of
relativity, which revolutionized our understanding of space, time, and
gravity. His special theory of relativity introduced the famous equation \( E
= mc^2 \), while his general theory of relativity provided a new description
of gravitation as the curvature of spacetime caused by mass and energy.
Einstein's contributions have had profound impacts on modern physics,
cosmology, and technology.
Q84: The instrument used to measure current is called ______.
A. Thermometer
B. Ammeter
C. Ohmmeter
D. Voltmeter
An ammeter is an instrument used to measure the electric current flowing
through a circuit. It is connected in series with the circuit component whose
current is to be measured. Ammeters are essential tools in electrical
engineering and diagnostics for ensuring proper current flow and identifying
issues like overcurrent conditions. They must have very low internal
resistance to avoid altering the circuit's behavior during measurement.
Q85: Automobiles are fitted with a device that shows the distance travelled.
Identify it.
A. Speedometer
B. Odometer
C. Altimeter
D. Tachometer
An odometer is the device in automobiles that measures and displays the total
distance traveled by the vehicle. It accumulates the distance based on the
rotation of the wheels and helps in tracking mileage for maintenance
schedules, fuel consumption, and resale value assessment. Some vehicles also
have trip odometers to measure distance for specific journeys. Understanding
odometer readings is important for vehicle management and performance
monitoring.
Q86: A lie detector apparatus is also known as a:
A. Barometer
B. Oscilloscope
C. Polygraph
D. Thermometer
A polygraph, commonly known as a lie detector, is an apparatus that measures
and records various physiological indicators such as blood pressure, pulse,
respiration, and skin conductivity while a person answers questions. The
underlying principle is that deceptive answers may produce physiological
responses different from those associated with truthful answers. Polygraphs
are used in law enforcement, security screenings, and other fields, although
their accuracy and reliability are subjects of debate.
Q87: Name the instrument used by physicians to measure blood pressure.
A. Barometer
B. Stethoscope
C. Sphygmomanometer
D. Thermometer
A sphygmomanometer is the instrument used by physicians to measure blood
pressure. It typically consists of an inflatable cuff to restrict blood flow,
a measuring unit (mercury or aneroid gauge), and a mechanism for inflation and
deflation. During measurement, the cuff is inflated to constrict the artery,
then slowly deflated while listening with a stethoscope to determine systolic
and diastolic pressures. Accurate blood pressure measurement is crucial for
diagnosing and managing cardiovascular conditions.
Q88: With the help of which device is potential difference measured?
A. Voltmeter
B. Ohmmeter
C. Multimeter
D. Ammeter
A voltmeter is the device used to measure the potential difference (voltage)
between two points in an electrical circuit. It is connected in parallel with
the component across which the voltage is to be measured. Voltmeters must have
high internal resistance to minimize the current drawn from the circuit,
ensuring accurate measurements without significantly affecting the circuit's
operation. Understanding voltage measurements is essential for electrical
troubleshooting and circuit design.
Q89: Which instrument is measured by the transfer of heat?
A. Hygrometer
B. Calorimeter
C. Barometer
D. Thermometer
A calorimeter is an instrument used to measure the amount of heat transferred
during a chemical reaction, phase transition, or physical process. It
typically consists of an insulated container to minimize heat exchange with
the environment, a thermometer to measure temperature changes, and sometimes
additional components to stir or contain the reactants. Calorimeters are
essential in thermodynamics, chemistry, and material science for studying
energy changes and reaction energetics.
Q90: Which device is used to measure the force acting on an object?
A. Spring balance
B. Ammeter
C. Calorimeter
D. Barometer
A spring balance is a device used to measure force by the amount a spring is
stretched or compressed. The force applied to the spring causes a displacement
that is proportional to the force, allowing the measurement of weight or other
forces. Spring balances are simple, portable, and widely used in various
applications, including weighing objects, measuring tension, and in physics
experiments to study force and motion relationships.
Q91: In case of a projectile motion, where is the kinetic energy minimum?
A. Kinetic energy remains constant
B. At the highest point
C. At the ground level
D. At the launch point
In projectile motion, the kinetic energy is minimum at the highest point of
the trajectory. This is because, at this point, the vertical component of the
velocity is zero, and only the horizontal component remains. Consequently, the
total kinetic energy, which depends on the square of the velocity, is reduced
compared to other points in the trajectory where both horizontal and vertical
components contribute to the velocity. Understanding energy distribution in
projectile motion is essential in mechanics and sports science.
Q92: How many laws of motion were given by Isaac Newton?
A. Four
B. Three
C. Two
D. One
Isaac Newton formulated three fundamental laws of motion, which are
foundational to classical mechanics. Newton's First Law (Law of Inertia)
describes the motion of objects in the absence of external forces. Newton's
Second Law quantifies the relationship between force, mass, and acceleration
(\( F = ma \)). Newton's Third Law states that for every action, there is an
equal and opposite reaction. These laws are essential for understanding and
predicting the behavior of objects under various force conditions.
Q93: The force acting on a unit area of a surface is called?
A. Stress
B. Pressure
C. Force Density
D. Tension
Pressure is defined as the force acting per unit area on a surface, expressed
as \( P = \frac{F}{A} \), where \( F \) is the force and \( A \) is the area.
The SI unit of pressure is the pascal (Pa), which is equivalent to one newton
per square meter (N/m²). Pressure is a fundamental concept in fluid mechanics,
thermodynamics, and engineering, applicable in scenarios like atmospheric
pressure, hydraulic systems, and material stress analysis.
Q94: Stress at any point in a material is defined as ______.
A. Force per unit volume
B. Force per unit mass
C. Force per unit length
D. Resisting force per unit area
Stress is defined as the resisting force per unit area within materials
undergoing deformation. It is expressed as \( \sigma = \frac{F}{A} \), where
\( F \) is the force and \( A \) is the area over which the force is
distributed. Stress is a critical concept in material science and engineering,
used to analyze and predict how materials will behave under various load
conditions. It helps in designing structures that can withstand forces without
failure.
Q95: Which of the following quantities is expressed in Joule (J)? 1) work and
inertia 2) velocity and displacement 3) inertia and energy 4) work and energy
A. 4 only
B. 1 only
C. 3 only
D. 2 only
Both work and energy are measured in joules (J). Work is done when a force
moves an object over a distance (\( W = F \times d \)), and energy is the
capacity to perform work. Inertia, however, is measured in kilogram meters per
second squared (kg·m/s²) as it relates to mass and acceleration. Velocity is
measured in meters per second (m/s), and displacement in meters (m).
Therefore, only work and energy share the same unit, joules.
Q96: 1 kilowatt hour (kWh) of energy = ______ joule.
A. \( 3.6 \times 10^5 \) J
B. \( 3.6 \times 10^3 \) J
C. \( 3.6 \times 10^6 \) J
D. \( 3.6 \times 10^4 \) J
One kilowatt hour (kWh) is equal to \( 3.6 \times 10^6 \) joules (J). This
conversion is derived from the fact that one kilowatt (kW) is \( 10^3 \) watts
and one hour is \( 3600 \) seconds, so \( 1 \, \text{kWh} = 10^3 \, \text{W}
\times 3600 \, \text{s} = 3.6 \times 10^6 \, \text{J} \). Understanding this
conversion is important for calculating energy consumption and costs in
electrical systems.
Q97: The kinetic energy possessed by an object of mass (m), and moving with a
uniform velocity (v) is:
A. \( mv^2 \)
B. \( \frac{1}{2}mv^2 \)
C. \( \frac{1}{2}mv \)
D. \( mv \)
Kinetic energy (\( Ek \)) is given by the formula \( Ek = \frac{1}{2}mv^2 \),
where \( m \) is mass and \( v \) is velocity. This equation quantifies the
energy an object possesses due to its motion. Kinetic energy is a scalar
quantity and is fundamental in various areas of physics, including mechanics,
thermodynamics, and energy conservation studies. Understanding kinetic energy
is essential for analyzing motion and designing systems that involve moving
objects.
Q98: What will be the value of the kinetic energy (Ek) of a moving body with
mass m, if its speed is doubled from v to 2v?
A. \( 4Ek \)
B. \( 3Ek \)
C. \( 2Ek \)
D. \( Ek \)
The kinetic energy of a body is given by \( Ek = \frac{1}{2}mv^2 \). If the
speed is doubled to \( 2v \), the new kinetic energy becomes \( Ek' =
\frac{1}{2}m(2v)^2 = \frac{1}{2}m(4v^2) = 4Ek \). Therefore, doubling the
speed of a body results in quadrupling its kinetic energy. This relationship
highlights the quadratic dependence of kinetic energy on velocity, which is
crucial in understanding energy requirements for speeding up objects and in
collision dynamics.
Q100: The correct relation between v, u, and f for a spherical mirror is:
A. \( f = \frac{u + v}{2} \)
B. \( \frac{1}{f} = \frac{1}{u} + \frac{1}{v} \)
C. \( f = u + v \)
D. \( \frac{1}{f} = \frac{1}{u} - \frac{1}{v} \)
The mirror formula for spherical mirrors is \( \frac{1}{f} = \frac{1}{u} +
\frac{1}{v} \) , where f is the focal length, u is the object distance, and v
is the image distance.
This relation is fundamental in geometrical optics for determining image
formation by mirrors. Proper application of the sign conventions is essential
for accurate calculations and understanding the nature of the image formed
(real or virtual, upright or inverted).
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