Category: Class 11 Physics Objective Questions

250+ TOP MCQs on Oscillations – Simple Harmonic Motion and Uniform Circular Motion | Class 11 Physics

Physics Multiple Choice Questions on “Oscillations – Simple Harmonic Motion and Uniform Circular Motion”.

1. In the given phasor diagram what should be the minimum velocity of particle 2 at mean position so that it catches particle 1 before it reaches the extreme position? The projection of motion of particle 1 on x-axis is governed by the equation: x = 4sin(2t).

a) 8m/s
b) 16m/s
c) 4m/s
d) 12m/s
Answer: b
Clarification: 2 has to catch 1 before it covers a quarter of the circle. In this time, 2 will have to cover half the circle. Thus, it should have twice the velocity of particle 1 at each corresponding point. Thus, minimum velocity of particle 2 at mean position is twice that of 1 at mean position
= 2*( 4*2)
= 16m/s.

2. A ball tied to the end of a string of length 10cm is rotated with constant speed of 2m/s in a circle about the origin. Find the equation of projection of the ball on the x-axis. At t=0, the ball makes an angle of 45° with the x-axis & is travelling in anticlockwise direction.
a) 0.1sin(20t + 3π/4)
b) 0.1cos(20t + π/4)
c) 10sin(20t + π/4)
d) 10cos(20t – 3π/4)
Answer: a
Clarification: Let the equation of motion be: x = A sin(wt + a). The amplitude is 0.1m, w = 2/0.1 = 20s-1. a will be either π/4 or 3π/4 since at t=0, x = A/√2. The ball is travelling in anticlockwise direction so its velocity of projection at t=0 should be towards the origin and therefore negative. v = Aw cos(wt + a).
At t=0, v is negative, so a will be 3π/4. Therefore eqn is: x = 0.1sin(20t + 3π/4)

3. A ball is hanging from a thread. It is given some speed such that the ball makes a complete circle under the influence of gravity. The projection of the ball on the x-axis will be an SHM. True or False?

a) True
b) False
Answer: b
Clarification: For the projection of a circular motion to be a SHM, the speed of a particle in circular motion should be constant, but under the influence of gravity, the speed will be variable. Thus, the motion of projection will be oscillatory but not simple harmonic.

4. If a body in uniform circular motion covers the given angle in 0.5s, what is the time period of projection, on the x-axis, undergoing SHM? Assume it moves anti-clockwise.

a) 4s
b) 1s
c) 2s
d) 3s
Answer: a
Clarification: The given motion represents the body moving from A/√2 to 0.
The time taken from 0 to A/√2 will also be the same.
wt = angle covered by circular motion, where w is angular frequency = 2π/T.
w*0.5 = π/4. w = π/2.
T = 2π/w = 4s.

5. The angular speed of a body in uniform circular motion is the same as the angular frequency of SHM of its projection. True or False?
a) True
b) False
Answer: a
Clarification: Let the angular speed of the body be w. Let it start from rest from the x-axis.
At any time the angle it has covered is wt.
The projection on x-axis is then given by: x = Asin(wt).
Thus, angular speed is the same as angular frequency of SHM.

250+ TOP MCQs on Introduction to Motion in a Straight Line | Class 11 Physics

Physics Multiple Choice Questions on “Introduction to Motion in a Straight Line”.

1. In which of the following states does a body possess kinetic energy?
a) Rest
b) Motion
c) When placed on a platform
d) In zero gravity
Answer: b
Clarification: The body moves in the state of motion. Hence it has a velocity and so kinetic energy. Kinetic energy = (1/2)mv2.

2. Which of the following types of motion can be used for describing the motion of a car on a straight road?
a) Rectilinear
b) Circular
c) Periodic
d) Harmonic
Answer: a
Clarification: The motion of a car on straight road is happening along a straight line. Hence the motion can be called rectilinear as rectilinear motion happens along a straight line. Rest all are non rectilinear motions.

3. Which of the following types of motion cannot describe the motion of a clock’s hands?
a) Rectilinear
b) Circular
c) Periodic
d) Harmonic
Answer: a
Clarification: The hands of a clock move in a circular manner. Hence, the motion exhibited is circular motion. Moreover, it happens periodically, so it is also periodic motion. But its is not rectilinear motion.

4. Which force can possibly act on a body moving in a straight line?
a) Tangential force
b) Friction force
c) Centrifugal force
d) Centripetal force
Answer: b
Clarification: In the physical world, no surface is frictionless. Hence whenever a body moves, the force of friction acts on it. Rest all forces act on the body only when it moves along a curve and not along a straight line.

5. What kind of motion is rectilinear motion?
a) One dimensional
b) Two dimensional
c) Three dimensional
d) Zero dimensional
Answer: a
Clarification: Rectilinear motion happens along a straight line. A straight line is one dimensional. Hence, rectilinear motion is one dimensional.

6. When a body is in the state of complete rest, what kind of energy does it possess?
a) Potential energy
b) Kinetic energy
c) Total energy
d) Heat energy
Answer: a
Clarification: When the body is in the state of rest, there is no motion. Hence there is no kinetic energy, hence the total energy of the body is stored as its potential energy. The total energy is the sum of kinetic and potential energies.

7. Which of the following are obtained by dividing total displacement by total time taken?
a) Average velocity
b) Instantaneous velocity
c) Uniform velocity
d) Speed
Answer: a
Clarification: The average velocity is obtained by dividing total displacement by total time taken. Instantaneous velocity is calculated at an instant and not over a period of time. Speed is distance divided by time. Velocity is said to be uniform when velocity at every instant is equal to the average velocity.

8. What is the rate of change of rate of change of displacement of a body?
a) Velocity
b) Acceleration
c) Force
d) Jerk
Answer: b
Clarification: The rate of change of displacement of a body is velocity. The rate of change of rate of displacement of a body, or rate of change of velocity is acceleration.

Physics,

250+ TOP MCQs on Laws of Motion Basics | Class 11 Physics

Physics Multiple Choice Questions on “Laws of Motion Basics”.

1. Which of the following laws of motion is related to inertia?
a) First law
b) Second Law
c) Third Law
d) Fourth Law
Answer: a
Clarification: The first law of motion states that a body remains in the state of motion or in the state of rest until and unless an external force is applied on it. This is also known as the law of inertia. Hence the answer is, the first law.

2. Which law of Newton helps in finding the force on a body?
a) First law
b) Second Law
c) Third Law
d) Fourth Law
Answer: b
Clarification: The second law of motion states that the net force applied on a body is proportional to the rate of change of momentum. On further experimentation, it was found that the force applied on a body is equal to the rate of change of momentum.

3. Which law of Newton helps in finding the reaction forces on a body?
a) First law
b) Second Law
c) Third Law
d) Fourth Law
Answer: c
Clarification: The third law of motion states that for every action there is an equal and opposite reaction. This law helps us in finding the reaction forces on a body. A classic example is the way we walk. We need to push the ground for walking and when we do so we experience an equal and opposite force on ourselves which helps us in walking.

4. The second law of motion, in mathematical form can be written as ____
a) F = dp/dt
b) F = ma
c) F = v(dm/dt)
d) F = mv
Answer: a
Clarification: The second law of motion states that the net force applied on a body is equal to the rate of change of momentum. Momentum is usually represented by ‘p’. Hence, the answer is F = dp/dt.

5. When we walk on a boat in still water, the boat will ______
a) Move ahead
b) Move backwards
c) Not move
d) Move sideways
Answer: b
Clarification: The third law of motion applies in this case. According to the third law of motion, for every action, there is an equal and opposite reaction. When we walk on the boat, the boat experiences an equal and opposite reaction force. Since very little resistance is offered by the still water, the boat will move backwards.

6. Which one of the following is not an example of the third law of motion?
a) Walking
b) Skiing
c) Walking on a boat
d) Cycling
Answer: b
Clarification: The third law of motion does not apply to skiing as in skiing we do not apply any force on the ground. The motion is caused by gravity and extremely less friction. In all the other cases, a force is applied on the ground or the other body, the reaction of which causes the motion.

7. Which of the following is the correct formulation for the second law of motion?
a) F = m(dv/dt)
b) F = ma
c) F = v(dm/dt) + ma
d) F = mv2
Answer: c
Clarification: The second law of motion states that the net force applied on a body is equal to the rate of change of momentum. Hence, F = dp/dt. p = mv. Therefore, F = m(dv/dt) + v(dm/dt) = v(dm/dt) + ma.

250+ TOP MCQs on Various Forms of Energy : The Law of Conservation of Energy | Class 11 Physics

Physics Question Paper on “Various Forms of Energy : The Law of Conservation of Energy”.

1. Which of the following statements are true?
a) Energy can be created and destroyed
b) Energy cannot be created but only destroyed
c) Energy cannot be destroyed but only created
d) Energy can neither be created nor destroyed
Answer: d
Clarification: According to the law of conservation of energy, energy can neither be created nor destroyed but can only be changed from one form to another. This is also one of the fundamental concepts of thermodynamics.

2. The dimensions of energy are _____
a) [ML2T-2]
b) [MLT-2]
c) [ML2T-1]
d) [MLT-1]
Answer: a
Clarification: Energy = Force x Displacement
Units of energy = kg x (m/s2) x m
= kg x m2 x s-2
Therefore;
Dimensions of energy = [ML2T-2].

3. Which of the following is not true?
a) Energy of an open system can be varied
b) Energy cannot be created
c) Energy cannot be destroyed
d) Energy cannot be transformed
Answer: d
Clarification: According to the law of conservation of energy, energy can neither be created nor destroyed but can only be changed from one form to another. Energy in an open system can be varying because of constant matter and radiation exchanges with the surrounding universe.

4. The law of conservation of energy is not applicable to mechanical systems as they require energy input to keep working.
a) True
b) False
Answer: b
Clarification: The law of conservation of energy is applicable to mechanical systems but it may not necessarily be applicable to a “machine” that requires constant power input to operate because it would then essentially be an open system.

5. The energy possessed by an object because of its motion is termed _____
a) potential energy
b) kinetic energy
c) nuclear energy
d) solar energy
Answer: b
Clarification: An object in motion possesses a velocity “v” at any instant of time.
This energy is termed “kinetic energy” and is given by;
Kinetic Energy = 1/2 x m x v2
where;
m = Mass of the object in motion

6. The maximum potential energy in a roller coaster is at _____
a) the top of the steep climb
b) somewhere during the climb
c) somewhere during the descent
d) the lowest point after the climb
Answer: a
Clarification: The potential energy is given by;
PE = m x g x h
where;
PE = Potential energy
m = Mass of the object
g = Acceleration due to gravity
h = Height of the object
Hence, the higher the object, the greater the potential energy.

7. Fire is a form of _____
a) solar energy
b) thermal energy
c) gravitational energy
d) kinetic energy
Answer: b
Clarification: Thermal energy is the consequence of the temperature of an object that is transferred in the form of heat from a source of greater temperature to a region or object of lower temperature by modes such as conduction, convection or radiation.

8. When a roller coaster is at the top of a steep hill, its potential energy is maximum. When it hurdles down the slope and comes to the bottom, the potential energy reduces greatly. Hence we can say that the law of conservation of energy is not valid here since energy is destroyed.
a) True
b) False
Answer: b
Clarification: When a roller coaster is at the top of a steep hill, its potential energy is maximum. When it hurdles down the slope and comes to the bottom, the potential energy reduces greatly. However, kinetic energy increases. Thus, there is a change from potential energy to kinetic energy and hence no destruction of energy.

9. When a person intakes 3000 kcal of food, he is able to do work requiring energy of 2500 kcal. This means that the human body destroys a fraction of energy obtained from food.
a) True
b) False
Answer: b
Clarification: If a person consumes 3000 kcal of food and does a work requiring 2500 kcal of energy, the rest of the 500 kcal is mostly used for the metabolic activities of the body and some are lost in the form of heat energy to the atmosphere.

10. For a freely falling body, which of the following quantities will not change?
a) Total kinetic energy
b) Total potential energy
c) Total mechanical energy
d) Insufficient data
Answer: c
Clarification: For a body falling freely under the influence of gravity, the velocity increases as heigh decreases. Hence, there is a reduction in potential energy but an increase in kinetic energy. However, the total mechanical energy, i.e., the sum of potential and kinetic energy always remains constant as per the law of conservation of energy.

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250+ TOP MCQs on The Gravitational Constant | Class 11 Physics

Physics Multiple Choice Questions on “The Gravitational Constant”.

1. What is the value of universal gravitational constant?
a) 6.022 x 1023
b) 6.67 x 10-11 N m2/kg2
c) 1.602 x 10-19 C
d) 9.81 m/s2
Answer: b
Clarification: 6.022 x 1023 is the Avogadro number.
6.67 x 10-11 N m2/kg2 is the value of universal gravitational constant.
1.602 x 10-19 C is the charge of a proton.
9.81 m/s2 is the acceleration due to gravity on the surface of the earth.

2. The gravitational constant is an empirical constant.
a) True
b) False
Answer: a
Clarification: The gravitational constant is the value of the slope of the graph “gravitational force versus (product of masses) / (square of the distance between them). So, it is not a derived constant, but an empirical one.

3. The value of universal gravitational constant changes is which of the following medium?
a) Air
b) Water
c) Plasma
d) The gravitational constant is independent of the medium
Answer: d
Clarification: Since the gravitational constant is an empirical constant, it does not vary with the medium. Hence, the value of the gravitational constant is the same in any part of the known universe.

4. What are the dimensions of universal gravitational constant?
a) [M2L3T2]
b) [M-1 L3 T-2]
c) [M-1 L3 T2]
d) [M1 L3 T-2]
Answer: b
Clarification: N m2/kg2 are the units of universal gravitational constant.
N m2/kg2 = m3/ (kgs2)
= m3kg-1s-2
Hence, the dimensions are [M-1 L3 T-2].

5. The value of gravitational constant was first determined by _____
a) Albert Einstein
b) Isaac Newton
c) Henry Cavendish
d) Stephen Hawking
Answer: c
Clarification: The value of gravitational constant was first experimentally determined by Henry Cavendish in the year 1798. It is also known as the Cavendish Gravitational Constant.

6. What apparatus did Henry Cavendish use in his experiment to determine the gravitational constant?
a) 1 bar, 1 small sphere and 1 large sphere
b) 1 bar, 2 small spheres and 2 large spheres
c) 2 bar, 1 small sphere and 2 large spheres
d) 2 bar, 2 small spheres and 1 large sphere
Answer: b
Clarification: Henry Cavendish used 1 bar, 2 small spheres and 2 large spheres in his experiment to determine the gravitational constant. By measuring the torque and angle of deflection produced due to the proximity of large spheres to the small ones, Henry Cavendish was able to determine the universal gravitational constant.

7. What material were the spheres made up of in Henry Cavendish’s experiment?
a) Lead
b) Steel
c) Iron
d) Wood
Answer: a
Clarification: Henry Cavendish used lead spheres in his experiment because lead was easily available at the time. Iron was also abundantly available. However, Henry Cavendish chose lead because it is denser than iron and the mass of lead is about 44% higher than that of iron for the same size of the sphere – this would lead to a larger gravitational force which is easier to measure.

250+ TOP MCQs on Fluids Mechanical Properties Pressure | Class 11 Physics

Physics MCQs for Class 11 on “Fluids Mechanical Properties Pressure – 2”.

1. A nail is made pointed at its end to ensure that pressure is more for a given amount of force applied on it. True or False?
a) True
b) False

Answer: a
Clarification: Pressure is defined as force per unit area. And we need more pressure to drive the nail easily into the wall. So we make the nail pointed as it has a much lesser area than a blunt end.

2. Which device is used to measure pressure?
a) Odometer
b) Barometer
c) Dynamometer
d) Hydrometer

Answer: b
Clarification: Barometer is a device used to measure air pressure. Odometer is a device used to measure the distance travelled by a wheeled vehicle (it is the speed indicator in your vehicle). Dynamometer is a device used to measure torque or rpm of an engine. Hydrometer is used to measure specific gravity of liquids. Also keep in mind that the liquid used in a barometer is mercury.

3. Which of the following quantities has the same S.I. unit as that of pressure?
a) Work
b) Energy / Velocity
c) Energy / Displacement
d) mass X (velocity)2/Volume

Answer: d
Clarification: The S.I. unit of pressure is N/m2.
Work has the unit of Nm.
Energy/Velocity has the unit of Nm/(m/s) = Ns.
The unit of energy/disp is Nm/m = N.
The unit of mass X (velocity) 2/Volume is same as that of energy per unit volume because mass X (velocity)2 is equal to energy,
which is in turn equal to Nm/m3 = N/m2, therefore this is the correct option.

4. Pressure is a vector quantity. True or False?
a) True
b) False

Answer: b
Clarification: When we talk about pressure at a point, we say it is exerted in all directions at that point, so it is not a vector quantity. As a vector quantity should have fixed direction with magnitude.

5. Assume a force of 30 N is distributed over a surface of area 2m2 in such a way that at each point force can be considered to act at an angle of 30° to the normal at that point. What will be the value of pressure on that plane?
a) 7.5 Pa
b) 7.5(sqrt{3}) Pa
c) 15 Pa
d) 15(sqrt{3}) Pa

Answer: b
Clarification: One important thing to keep in mind is that pressure at a point is the normal component of force per unit area, NOT total force per unit area.
So, here we will take the normal component of 30N force, i.e:
30cos(30°)=15(sqrt{3}).
Press = F/A = 15(sqrt{3})/2
= 7.5(sqrt{3}) Pa.

6. A car containing a beaker of water is moving horizontally on a level road. Consider two points, A & B, inside the water such that they are on the same horizontal level and are separated by a distance L. Which of the following options is correct regarding the pressure differences between those two points?
a) If car is accelerating with acceleration a, PA – PB = ρgL
b) If car is accelerating with acceleration a, PA – PB = 0
c) If car is moving with constant velocity, PA – PB = 0
d) If car is moving with constant acceleration a, PA – PB = ρ (g+a)L

Answer: c
Clarification: When the car is moving with constant velocity, points on the same horizontal level will have the same pressure.
So, PA – PB = 0.
When the car moves with constant acceleration the pressure difference between those two points will be ρaL,
as the pressure difference will be responsible for providing acceleration to the small fluid column of volume L*dA between points A & B
(where dA is an area of small element that we think of).