Physics Question MCQs India

Q 1.By how much the orbital velocity of Moon has to increase for it to cease to remain the earth’s satellite?
A. 2 times
B. 3 times
C. √3 times
D. √2 times

Show Answer Answer:-D. √2 times
Explanation If the speed of a satellite orbiting close to the earth is made √2 times (or increased by 41%) then it will escape from the gravitational field. Moon is a natural satellite of earth.


Q 2.What is the ratio of change in configuration to the original configuration called as?
A. Elasticity
B. Stress
C. Strain
D. Rebound

Show Answer Answer:-C. Strain
Explanation The ratio of change in configuration to the original configuration is called strain. Strain are of three types : 1. Linear 2. Volumetric 3. Shearing


Q 3.Which of the following is correct about Pressure?
A. Pressure is a scalar quantity but obeys vector laws
B. Pressure is a vector quantity
C. Pressure is a scalar quantity
D. None of the above

Show Answer Answer:-C. Pressure is a scalar quantity
Explanation Pressure is a scalar quantity. Pressure is derived from Force which is a vector quantity but still pressure is a scalar. The reason for this is that pressure always acts perpendicular to the surface it acts upon.


Q 4.Which of the following factors affect the Surface Tension?
A. Area of Surface
B. Nature of liquid
C. Both a and b
D. None of the above

Show Answer Answer:-B. Nature of liquid
Explanation The Surface tension depends only on the nature of liquid and is independent of the area of surface or length of line considered. Surface tension of a liquid is measured by the force acting per unit length on either side of an imaginary line drawn on the free surface of liquid.


Q 5.Which is correct about the height of a capillary column of a liquid, at a particular temperature, as per Jurin’s law?
A. equal to the diameter of the tube
B. directly proportional to the diameter of the tube

C. half of the diameter of the tube
D. inversely proportional to the diameter of the tube

Show Answer Answer:-D. inversely proportional to the diameter of the tube
Explanation Jurin’s law: the height of a capillary column of a liquid at a particular temperature is inversely proportional to the diameter of the tube.


Q 6.What is the relationship between excess pressure and the radius of the bubble?
A. inversely proportional to each other
B. are equal in value
C. directly proportional to each other
D no relationship

Show Answer Answer:-A. inversely proportional to each other
Explanation Excess pressure is inversely proportional to the radius of bubble (or drop). It means that the pressure inside a smaller bubble is higher than inside a larger bubble.


Q 7.What is the density of water at 4°?
A. 1.0 × 103 kg m–3
B. 1.0 × 102 kg m–3
C. 1.0
D. 10 kg m–3

Show Answer Answer:-A. 1.0 × 103 kg m–3
Explanation The density of water at 4°C (277 K) is 1.0 × 103 kg m–3. The relative density of a substance is the ratio of its density to the density of water at 4° C.


Q 8.What is the density of whole blood at STP?
A. 3.57 × 103 kg m–3
B. 2
C. 5.55 × 103 kg m–3
D. 1.06 × 103 kg m–3

Show Answer Answer:-D. 1.06 × 103 kg m–3
Explanation The densities of some common fluids: 1. Whole blood: 1.06 × 103 kg m–3 2. Mercury:13.6 × 103 kg m–3 3. Ethyl alcohol: 0.86 × 103 kg m–3


Q 9.What is the relationship between the spring constant k and the spring length in case of spring pendulum?
A. spring constant is twice the spring length
B. spring constant is directly proportional to the spring length
C. spring constant is independent of the spring length
D. spring constant is inversely proportional to the spring length

Show Answer Answer:-D. spring constant is inversely proportional to the spring length
Explanation The spring constant of a spring pendulum is inversely proportional to the spring length.


Q 10.What kinds of waves are the ultrasonic waves in air produced by a vibrating quartz crystal?
A. Longitudinal
B. Transverse
C. Transverse and longitudinal
D. None of the above

Show Answer Answer:-A. Longitudinal
Explanation The ultrasonic waves in air produced by a vibrating quartz crystal are longitudinal waves.

Q 11.What is the focal length of a concave lense with number -5D?

A. 5 cm
B. 10 cm
C. 15 cm
D. 20 cm

Show Answer Answer:-D. 20 cm
Explanation A concave lens is a type of lens that has a thinner centre than edges, and it is sometimes called a diverging lens because it spreads out light rays that are parallel to its axis. The focal length of a lens is a measure of its ability to focus light, and it is defined as the distance from the lens to the point where the light rays converge. In the case of a concave lens with a power of -5D, the focal length would be equal to 1/5 of a meter, or 20 centimetres.

Q 12.Ohm is a unit of measuring _________?

A. Current
B. Voltage
C. Resistance
D. None of the above

Show Answer Answer:-C. Resistance
Explanation The ohm is the SI unit of electrical resistance. Electrical resistance of an object is the measure of its obstruction to the flow of electric current. It mainly depends on the material it is made of, cross sectional area of a conductor, length and temperature. The resistance of a conductor of unit cross-sectional area and unit length is known as Resistivity. The unit of resistivity is ohm-metre.

Q 13.An electrical fuse is used to interrupt excessive________?

A. Voltage
B. Current
C. Resistance
D. Inductance

Show Answer Answer:-B. Current
Explanation An electrical fuse is used to interrupt excessive current. A fuse is an electrical safety device that operates to provide overcurrent protection of an electrical circuit.

Q 14.A piece of Ice was tied with a string to a water bucket’s bottom, and the water bucket was filled with water with ice fully submerged in it. What would be the impact on the level of water when the ice melts away completely?

A. The level of water will go up
B. The level of water will first increase then come to the previous on
C. The level of water will remain unchanged
D. The level of water will go down

Show Answer Answer:-D. The level of water will go down
Explanation There are two dimensions of this experiment. One is when Ice floats in water and another is as mentioned in the question. When Ice floats in water, the level of water will remain unchanged when the ice melts away because in this situation, Ice replaced water which is `equal to its weight`. But when the floating ice is taken down in the bottom of the bucket and tied over there with a string, and let melt away, the level of water will come down because now the ice was replacing the water `equal to its volume `and Ice has a lower density of water. So The answer of this question is -The level of water will go down.

Q 15.By how many times are the Electrostatic forces stronger than the Gravitational Forces for a fixed distance?

A. 102
B. 1036
C. 1012
D. 2

Show Answer Answer:-B. 10.36
Explanation Electrostatic forces are 1036 times stronger than the Gravitational Forces for a fixed distance. Electrostatic forces may be attractive or repulsive depending upon the charges. Electrostatic forces are conservative forces and obey inverse square law.

Q 16.Which of the following pairs represent two scalar quantities?

A. Mass, Acceleration
B. Temperature, Torque
C. Distance, Speed
D. Gravitational Intensity, Work

Show Answer Answer:-C. Distance, Speed
Explanation The physical quantities which have only magnitude and no direction are called as Scalar quantities. Some examples of Scalar quantities: Work, Mass, Temperature, Distance, Speed.

Q 17.The forces acting at a point are called as:

A. Collinear forces
B. Coplanar forces
C. Unit forces
D. Concurrent forces

Show Answer Answer:-D. Concurrent forces
Explanation The forces which are acting at a point are called as concurrent forces. Note: When concurrent forces in equilibrium act on a body, the state of the body shall remain unchanged i.e. if the body is at rest, it will continue to be at rest. Similarly, a body will continue to move uniformly along the same straight line, if concurrent forces in equilibrium are applied on the body.

Q 18.The inability of a body to change its state of rest or motion is known as:

A. Force
B. Momentum
C. Displacement
D. Inertia

Show Answer Answer:-D. Inertia
Explanation Inertia is the property of matter by which it continues in its existing state of rest or uniform motion in a straight line, unless that state is changed by an external force. There are three types of Inertia: 1. Inertia of rest 2. Inertia of motion 3. Inertia of direction

Q 19.The thrust on the rocket is:

A. in the opposite direction of the rocket
B. in the same direction of the rocket
C. at 90° to the direction of the rocket
D. None of the above

Show Answer Answer:-A. in the opposite direction of the rocket
Explanation The thrust on the rocket is in the opposite direction of the rocket. The thrust is the force with which rocket moves upwards. F = -u (dm/dt)

Q 20.Which of the following is NOT correct about an inelastic collision?

A. Linear momentum is conserved
B. Total energy is conserved
C. Kinetic energy is conserved
D. Some or all the forces involved may be non-conservative in nature

Show Answer Answer:-C. Kinetic energy is conserved
Explanation Following are the basic characteristics of an inelastic collision: 1. Linear momentum is conserved 2. Kinetic energy is NOT conserved 3. Total energy is conserved 4. Some or all the forces involved may be non-conservative in nature

Q 21.Which of the following represents Kinematic viscosity?
A. Viscosity/density
B. Viscosity/area
C. Viscosity/temperature
D. Viscosity/mass

Show Answer Answer:-A. Viscosity/density
Explanation Kinematic viscosity is defined mathematically as the ratio of the viscosity of a fluid to its density. It is the measure of the resistive flow of a fluid under the influence of gravity.


Q 22.Which of these ratios give the viscosity of a fluid?
A. ratio of the shearing stress to the velocity gradient

B. ratio of the shearing stress to the weight of the fluid
C. ratio of the shearing stress to the density of fluid
D. ratio of the velocity gradient and shearing stress

Show Answer Answer:-A. ratio of the shearing stress to the velocity gradient
Explanation Viscosity is defined mathematically as the ratio of the shearing stress to the velocity gradient in a fluid. It is represented by the Greek letter η (eta).


Q 23.Which of the following waves is produced when inner shell electrons in atoms move from one energy level to a lower level?
A. Infrared
B. Ultraviolet
C. X-rays
D. Microwaves

Show Answer Answer:-B. Ultraviolet
Explanation Ultraviolet rays are produced when the Inner shell electrons in atoms move from one energy level to a lower level.


Q 24.Which of the following statements state that no process is possible whose sole result is the transfer of heat from a colder object to a hotter object?
A. Kevin-Plank statement
B. Clausius statement
C. Einstein’s statement
D. None of the above

Show Answer Answer:-B. Clausius statement
Explanation Clausius statement: No process is possible whose sole result is the transfer of heat from a colder object to a hotter object.


Q 25.Which of the following eye-defects is also known as far -sightedness?
A. Myopia
B. Cataract
C. Hypermetropia
D None

Show Answer Answer:-C. Hypermetropia
Explanation Hypermetropia is also known as far -sightedness. A person with hypermetropia can see distant objects clearly but cannot see nearby objects distinctly.


Q 26.What is the S.I. unit of electric charge?
A. Ampere
B. Coulomb
C. Joule
D. Watt

Show Answer Answer:-B. Coulomb
Explanation The SI unit of electric charge is coulomb (C), which is equivalent to the charge contained in nearly 6 × 1018 electrons.


Q 27.Which of the following is NOT a natural magnet?
A. lodestone
B. pyrrhotite
C. titanium
D. columbite

Show Answer Answer:-C. titanium
Explanation An example of a natural magnet is the lodestone, also called magnetite. Other examples are pyrrhotite, ferrite, and columbite.


Q 28.How can a moving coil galvanometer be converted into a voltmeter?
A. by introducing shunt resistance in parallel
B. by introducing large resistance in series
C. by introducing shunt resistance in series
D. None of the above

Show Answer Answer:-B. by introducing large resistance in series
Explanation A moving coil galvanometer can be converted into a voltmeter by introducing a resistance of a large value in series.


Q 29.What of following is equivalent to 1 a.m.u?
A. 1.660539 x 10-18 kg
B. 1.660539 x 10-21 kg
C. 1.660539 x 10-24 kg
D. 1.660539 x 10-27 kg

Show Answer Answer:-D. 1.660539 x 10-27 kg
Explanation 1 a.m.u = 1.660539 x 10-27 kg


Q 30.When is a p-n diode said to be forward biased?
A. when p-side is connected to the negative terminal of the battery
B. when n-side is connected to the positive terminal of the battery
C. when p-side is connected to the positive terminal of the battery
D. None of the above

Show Answer Answer:-C. when p-side is connected to the positive terminal of the battery
Explanation When an external voltage V is applied across a semiconductor diode such that p-side is connected to the positive terminal of the battery and n- side to the negative terminal.

Q 31.Outside of cooking utensils are generally left black from below because__:

A. it is difficult to clean daily.
B. black surface is a good conductor of heat.
C. black surface is a poor conductor of heat.
D. black surface is a good absorber of heat.

Show Answer Answer:-D. black surface is a good absorber of heat.
Explanation The outside surface of a utensil used for heating is coated black so that it may absorb more heat and make heating quicker. This is because black surface is both a good absorber and emitter of heat.

Q 32.The cooling by a desert Cooler is based on__:

A. Hot air replacement
B. Air dehydration
C. Evaporative Cooling
D. Air Rehydration

Hide Answer

Show Answer Answer:-
Explanation Nature’s most efficient means of cooling is through the evaporation of water. Desert coolers make use of evaporative cooling that works on the principle of heat absorption by moistures evaporation. As water is evaporated, heat energy is extracted from the air to produce the cooling effect.

Correct Answer: C [Evaporative Cooling]

Notes:

Q 33.The head mirror used by ENT doctors is__:

A. Concave
B. Convex
C. Plane
D. Plano-convex

Show Answer Answer:-A. Concave
Explanation A head mirror is mostly used for examination of the ear, nose or throat. It comprises a circular concave mirror, with a small hole in the middle, and is attached to a head band. The mirror is worn over the physician’s eye of choice, with the concave mirror surface facing outwards and the hole directly over the physician’s eye, providing illumination like a ring light.

Q 34.Which of these travels in glass with minimum velocity ?

A. red light
B. green light
C. violet light
D. yellow light

Show Answer Answer:-C. violet light
Explanation Red light has a longer wavelength than violet light and the other colours of visible light have intermediate wavelengths. As light passes from air into glass, there is reduction of velocity. Due to longer wavelengths, red waves travel fastest and is refracted the least, while violet waves travel the slowest and is refracted the most because of their smaller wave length.

Q 35.Which of the following phenomena is involved in Kaleidoscope?

A. Refraction
B. Reflection
C. Total Internal reflection
D. Diffraction

Show Answer Answer:-B. Reflection
Explanation A kaleidoscope is an optical instrument with two or more reflecting surfaces inclined to each other in an angle, so that one or more objects on one end of the mirrors are seen as a regular symmetrical pattern when viewed from the other end, due to repeated reflection. It operates on the principle of multiple reflection, where two or more reflectors are placed at an angle to one another.

Q 36.Which of the following controls the amount of light entering the eye?

A. Aqueous humour
B. Cornea
C. Iris
D. Crystalline lens

Show Answer Answer:-C. Iris
Explanation The pupil is the opening in the center of the iris. The size of the pupil determines the amount of light that enters the eye. The pupil size is controlled by the dilator and sphincter muscles of the iris.

Q 37.In MRI machine, which one of the following is used?

A. Sound wave
B. Magnetic wave
C. Ultra-sound wave
D. ‘X’-ray

Show Answer Answer:-B. Magnetic wave
Explanation Magnetic resonance imaging (MRI), nuclear magnetic resonance imaging (NMRI), or magnetic resonance tomography (MRT) is a medical imaging technique used in radiology to visualize internal structures of the body in detail. MRI makes use of the property of nuclear magnetic resonance (NMR) to image nuclei of atoms inside the body. An MRI scanner is a device in which the patient lies within a large, powerful magnet where the magnetic field is used to align the magnetization of some atomic nuclei in the body, and radio frequency fields to systematically alter the alignment of this magnetization. This causes the nuclei to produce a rotating magnetic field detectable by the scanner. and this information is recorded to construct an image of the scanned area of the body.

Q 38.In the remote control of television, electromagnetic waves used are__:

A. ultraviolet
B. microwave
C. radiowave
D. infrared

Show Answer Answer:-D. infrared
Explanation In remote control of television receivers at home, the functioning is dependent on the infra-red rays. These rays received by the thermionic valves regulate/control the working of television.

Q 39.Alpha particle is the nucleus of an atom of__:

A. Lithium
B. Hydrogen
C. Oxygen
D. Helium

Show Answer Answer:-D. Helium
Explanation Alpha particles (2He4) consist of two protons and two neutrons bound together into a particle identical to a helium nucleus, which is generally produced in the process of alpha decay. These particles travelling with 10% of velocity of light cause ionization.

Q 40.Which current flows in telephone line?

A. sound energy
B. mechanical energy
C. radio energy
D. electric energy

Show Answer Answer:-D. electric energy
Explanation The telephone system converts acoustic energy (sound) into electric energy. The electric energy travels along the phone wires and is converted back into acoustic energy at the receiving end. Interference is caused by the tiny imperfections in the wires carrying the electrical pulses.

Q 41.At what temperature (in degree celsius), the numerical values on Celsius and Fahrenheit scales become equal?

A. 40
B. -40
C. 273
D. -273

Show Answer Answer:-B. -40
Explanation To find the temperature when both are equal, we use an old algebra trick and just set ºF = ºC and solve one of the equations. So the temperature when both the Celsius and Fahrenheit scales are the same is -40 degrees.

Q 42.What type of mirror is used by motorists to see the road behind them?

A. Convex
B. Concave
C. Plane
D. Concavo-convex

Show Answer Answer:-A. Convex
Explanation A convex mirror provides for a larger field of view than a plane mirror. This is why they are useful. They are used whenever a mirror with a large field of view is needed. For example, the passenger-side rear view mirror on a car is convex. For making sun glasses and telescopes also convex mirror is used. It is used as reflector in street lamps so as to diverge light over a large area.

Q 43.When a brick is dropped in water, bubbles are seen to rise. This is due to which of the following reasons?

A. Water displaced by the brick
B. Air in water
C. Air in the pores of the brick
D. None of these

Show Answer Answer:-C. Air in the pores of the brick
Explanation A brick is made when mud is heated and hence it remains porous. When brick is dropped in water the air which was trapped in those pores rise up and hence form the bubbles.

Q 44.Low temperatures (Cryogenics) find application in?

A. space travel, surgery and magnetic levitation
B. surgery, magnetic levitation and telemetry
C. space travel, surgery and telemetry
D. space travel, magnetic levitation and telemetry

Show Answer Answer:-A. space travel, surgery and magnetic levitation
Explanation In physics, cryogenics is the study of the production of very low temperature (below –150 °C, – 238 °F or 123 K) and the behavior of materials at those temperatures. Application of cryogenics are in MRI. MRI is a method of imaging objects that uses a strong magnetic field to detect the relaxation of protons that have been perturbed by a radio-frequency pulse. This magnetic field is generated by electromagnets, and high field strengths can be achieved by using superconducting magnets. Traditionally, liquid helium is used to cool the coils because it has a boiling point of around 4 K at ambient pressure.  Cryogenic liquids are also used in the space program. For example, cryogens are used to propel rockets into space. A tank of liquid hydrogen provides the fuel to be burned and a second tank of liquid oxygen is provided for combustion.  Cryogenic processes are also used to supply “banks” storing eye corneas, blood, and sperm for future surgical procedures. In 1961 American surgeon Irving S. Cooper introduced a freezing technique called cryosurgery. Cryosurgery is relatively bloodless because the low temperatures used constrict the blood vessels, stemming the loss of blood.

Q 45.When a man in a train moving with a constant velocity drops a ball on the platform, the path of the ball as seen by an observer on platform will be__:

A. A parabola
B. A circle
C. A straight line
D. None of these

Show Answer Answer:-A. A parabola
Explanation In the reference frame of the platform the ball has initial horizontal velocity equal to the velocity of the train. The vertical direction is the same observed on the train because both observers agree that gravity is acting on the ball causing an acceleration g. But, in the platform’s reference frame it already had x-velocity, and the resultant path would be a parabola.

Q 46.Which law of Newton supports the fact that it is difficult to fix a nail on a freely suspended wooden frame?

A. Law of inertia
B. Newton’s third law
C. Newton’s second law
D. Pascal’s law

Show Answer Answer:-B. Newton’s third law
Explanation According to Newton’s third law, for every action, there is an equal and opposite reaction. When trying to fix a nail to a freely suspended wooden frame, as the hammer applies a downward force to the nail, the nail applies an equal upward force to the frame. This causes the frame to bounce away, making it difficult to fix the nail. Therefore, Newton’s third law best supports the fact that fixing a nail to a freely suspended frame is difficult, as the frame bounces away due to the equal and opposite reaction force.

Q 47.If the acceleration due to gravity on the surface of earth is g, then the acceleration due to gravity on the surface of a planet whose mass is same as that of earth and radius is twice as that of earth is__:

A. g/4
B. g/2
C. 4g
D. 2g

Show Answer Answer:-A. g/4
Explanation Acceleration due to gravity is given by the formula : g = GM/r2 According to the question, mass of the second planet is same as that of earth and radius is twice So, using the formula of g, we get the acceleration due to gravity of the second planet as g/4.

Q 48.If the velocity of a body is doubled its momentum _______.

A. remains same
B. becomes half
C. doubles
D. becomes 4 times

Show Answer Answer:-C. doubles
Explanation Momentum depends upon the variables mass and velocity. In terms of an equation, the momentum of an object is equal to the mass of the object times the velocity of the object. The momentum is directly proportional to an object’s mass and directly proportional to the object’s velocity. If the velocity of a body is doubled its momentum also doubles.

Q 49.Water will not be vaporized if__:

A. the temperature is 0°C
B. the humidity is 0%
C. the humidity is 100%
D. the temperature is 100°C

Show Answer Answer:-C. the humidity is 100%
Explanation If the relative humidity is 100 percent, water will not evaporate as the air is already saturated with moisture. When relative humidity approaches 100 percent, condensation can occur. The lower the relative humidity, the easier it is for moisture to evaporate. Therefore, people living in hot coastal areas suffen from heat stagnation.

Q 50.The wall of a dam is made thicker at the bottom than at the top because the pressure exerted by the water on the wall__:

A. depends on the thickness of the wall
B. increases with depth of the wall
C. increases with height of the wall
D. depends on the area of the wall

Show Answer Answer:-B. increases with depth of the wall
Explanation According to Pascal’s law of pressure, with the increasing depth, the pressure exerted by the water also increases. Hence, to resist the pressure which is exerted equally in all directions with the increasing depth, the thickness of walls increases.

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