Physics · NDA previous year questions

The free fall acceleration g increases as one proceeds, at sea level, from the equator toward either pole. The reason is

1. A.Earth is a sphere with same density everywhere
2. B.Earth is a sphere with different density at the polar regions than in the equatorial regions
3. C.Earth is approximately an ellipsoid having its equatorial radius greater than its polar radius by 21 km
4. D.Earth is approximately an ellipsoid having its equatorial radius smaller than its polar radius by 21 km

MCQ (More than One Correct Answer) Which one of the following statements is correct?

1. A.The measurement of mass taken by a spring weighing balance is correct at the place where the spring balance is calibrated for
2. B.The measurement of mass taken by a spring weighing balance is correct at all places
3. C.The measurement of mass taken by a spring weighing balance is correct at the places where the acceleration due to gravity is same with the place where the spring balance is calibrated for
4. D.A spring balance cannot be used to measure mass at any place

Which one of the following is not a contact force?

1. A.Push force
2. B.Gravitational force
3. C.Frictional force
4. D.Strain force

When a force of 1 newton acts on a mass of 1 kg which is able to move freely, the object moves in the direction of force with a/an

1. A.speed of 1 km/s
2. B.acceleration of 1 $m/{\mathrm{s}}^2$
3. C.speed of 1 m/s
4. D.acceleration of 1 $km/{\mathrm{s}}^2$

Two balls, $A$ and $B$, are thrown simultaneously, $A$ vertically upward with a speed of $20m/s$ from the ground and $B$ vertically downward from a height of $40\mathrm{m}$ with the same speed and along the same line of motion. At what points do the two balls collide by taking acceleration due to gravity as $9.8m/{\mathrm{s}}^2$ ?

1. A.The balls will collide after 3s at a height of 30.2 m from the ground
2. B.The balls will collide after 2s at a height of 20.1 m from the ground
3. C.The balls will collide after 1s at a height of 15.1 m from the ground
4. D.The balls will collide after 5s at a height of 20 m from the ground

One kilowatt hour is equal to

1. A.$36\times 10^3$ joule
2. B.$36\times 10^5$ joule
3. C.$10^3$ joule
4. D.$10^5$ joule

Consider the following circuit : The equivalent resistance of the circuit will be

1. A.$12\Omega$
2. B.$8\frac{11}{12}\Omega$
3. C.$9\frac{1}{11}\Omega$
4. D.$\frac{24}{25}\Omega$

A racing car accelerates on a straight road from rest to a speed of 50 m/s in 25 s. Assuming uniform acceleration of the car throughout, the distance covered in this time will be

1. A.625 m
2. B.1250 m
3. C.2500 m
4. D.50 m

A given conductor carrying a current of 1 A produces an amount of heat equal to 2000 J. If the current through the conductor is doubled, the amount of heat produced will be

1. A.2000 J
2. B.4000 J
3. C.8000 J
4. D.1000 J

A lady is standing in front of a plane mirror at a distance of 1 m from it. She walks 60 cm towards the mirror. The distance of her image now from herself (ignoring the thickness of the mirror) is

1. A.40 cm
2. B.60 cm
3. C.80 cm
4. D.120 cm

A simple circuit contains a 12 V battery and a bulb having 24 ohm resistance. When you turn on the switch, the ammeter connected in the circuit would read

1. A.0·5 A
2. B.2 A
3. C.4 A
4. D.5 A

Three resistors with magnitudes 2, 4 and 8 ohm are connected in parallel. The equivalent resistance of the system would be

1. A.less than 2 ohm
2. B.more than 2 ohm but less than 4 ohm
3. C.4 ohm
4. D.14 ohm

Two bodies A and B are moving with equal velocities. The mass of B is double that of A. In this context, which one of the following statements is correct?

1. A.Momentum of B will be double that of A.
2. B.Momentum of A will be double that of B.
3. C.Momentum of B will be four times that of A.
4. D.Momenta of both A and B will be equal.

The S.I. unit of acceleration is

1. A.$\mathrm{m}{\mathrm{s}}^{-1}$
2. B.$\mathrm{m}{\mathrm{s}}^{-2}$
3. C.$\mathrm{cm}{\mathrm{s}}^{-2}$
4. D.$\mathrm{km}{\mathrm{s}}^{-2}$

An object is placed at the centre of curvature of a concave mirror of focal length 16 cm. If the object is shifted by 8 cm towards the focus, the nature of the image would be

1. A.real and magnified
2. B.virtual and magnified
3. C.real and reduced
4. D.virtual and reduced

A pencil is placed upright at a distance of 10 cm from a convex lens of focal length 15 cm. The nature of the image of the pencil will be

1. A.real, inverted and magnified
2. B.real, erect and magnified
3. C.virtual, erect and reduced
4. D.virtual, erect and magnified

Suppose the force of gravitation between two bodies of equal masses is F. If each mass is doubled keeping the distance of separation between them unchanged, the force would become

1. A.F
2. B.2 F
3. C.4 F
4. D.$\frac{1}{4}$ F

A body has a free fall from a height of 20 m. After falling through a distance of 5 m, the body would

1. A.lose one-fourth of its total energy
2. B.lose one-fourth of its potential energy
3. C.gain one-fourth of its potential energy
4. D.gain three-fourth of its total energy

Mass of a particular amount of substance 1. is the amount of matter present in it. 2. does not vary from place to place. 3. changes with change in gravitational force. Select the correct answer using the code given below:

1. A.1, 2 and 3
2. B.1 and 2 only
3. C.2 and 3 only
4. D.1 only

The impulse on a particle due to a force acting on it during a given time interval is equal to the change in its

1. A.force
2. B.momentum
3. C.work done
4. D.energy

The motion of a car along a straight path is shown by the following figure: The car starts from O and reaches at A, B and C at different instants of time. During its motion from O to C and back to B, the distance covered and the magnitude of the displacement are, respectively

1. A.25 km and 60 km
2. B.95 km and 35 km
3. C.60 km and 25 km
4. D.85 km and 35 km

The brightness of a star depends on its

1. A.size and temperature only
2. B.size and distance from the earth
3. C.size, temperature and mass
4. D.size, temperature and distance from the earth

Which one of the following statements is correct?

1. A.The image formed by a concave mirror for an object lying at infinity is at the principal focus, highly diminished, real and inverted
2. B.A ray of light parallel to the principal axis after reflection from a concave mirror appears to diverge from the principal focus of the mirror
3. C.The focal length of a spherical mirror is double of its radius of curvature
4. D.A ray of light travelling from a rarer medium to a denser medium bends away from the normal

MCQ (More than One Correct Answer) Which one of the following statements is not correct?

1. A.In steady flow of a liquid, the velocity of liquid particles reaching at a particular point is the same at all points
2. B.Steady flow is also called streamlined flow
3. C.In steady flow, each particle may not follow the same path as taken by a previous particle passing through that point
4. D.Two streamlines cannot intersect each other

A brass ball is tied to a thin wire and swung so as to move uniformly in a horizontal circle. Which of the following statements in this regard is / are true? 1. The ball moves with constant velocity 2. The ball moves with constant speed 3. The ball moves with constant acceleration 4. The magnitude of the acceleration of the ball is constant Select the correct answer using the code given below:

1. A.1 only
2. B.1 and 3
3. C.1, 2 and 4
4. D.2 and 4 only