Physics · NDA previous year questions

A force applied on a body is represented as $$\vec{F}=6\hat{i}-8\hat{j}+10\hat{k}$$ and accelerates it at $1m/{\mathrm{s}}^2$. The mass of the body is

1. A.$10\mathrm{kg}$
2. B.$10\sqrt{2}\mathrm{kg}$
3. C.$2\sqrt{10}\mathrm{kg}$
4. D.$8\mathrm{kg}$

A force $\vec{F}$, acting on an electric charge $q$, in presence of an electro-magnetic field, moves the charge parallel to the magnetic field with velocity $\vec{v}$. Then $\vec{F}$ is equal to (where $\vec{E}$ and $\vec{B}$ are electric field and magnetic field respectively)

1. A.$q\vec{E}$
2. B.$q(\vec{v}\times \vec{B})$
3. C.$q(\vec{v}\times \vec{E})$
4. D.$q\vec{B}$

Which of the following are the correct parameters for the common domestic power supply in India?

1. A.220 V, 110 Hz
2. B.220 V, 50 Hz
3. C.110 V, 220 Hz
4. D.110 V, 50 Hz

A ray of light travels from a medium of refractive index $n_1$ to a medium of refractive index $n_2$. If angle of incidence is $i$ and angle of refraction is $r$, then $\frac{\sin i}{\sin r}$ is equal to

1. A.$n_1$
2. B.$n_2$
3. C.$\frac{n_2}{n_1}$
4. D.$\frac{n_1}{n_2}$

Light waves projected on oil surface show seven colours due to the phenomenon of

1. A.polarization
2. B.refraction
3. C.reflection
4. D.interference

Statement II : Magnetic poles occur in pair.

1. A.Both the statements are individually true and Statement II is the correct explanation of Statement I
2. B.Both the statements are individually true but Statement II is not the correct explanation of Statement I
3. C.Statement I is true but Statement II is false
4. D.Statement I is false but Statement II is true

Statement I : A body moving in a circular path is acted upon by the centripetal force. Statement II : Centripetal force acting on the body is doing work to keep it rotating in the circular path.

1. A.Both the statements are individually true and Statement II is the correct explanation of Statement I
2. B.Both the statements are individually true but Statement II is not the correct explanation of Statement I
3. C.Statement I is true but Statement II is false
4. D.Statement I is false but Statement II is true

If the motion of an object is represented by a straight line parallel to the time axis in a distance-time graph, then the object undergoes

1. A.an accelerated motion
2. B.a decelerated motion
3. C.a uniform non-zero velocity motion
4. D.a zero velocity motion

Kerosene oil rises in a wick of lantern because of

1. A.buoyancy of air
2. B.diffusion of the oil through the wick
3. C.capillary action in the wick
4. D.gravitational pull of the wick

Two cars $A$ and $B$ have masses $m_A$ and $m_B$ respectively, with $m_A>m_B$. Both the cars are moving in the same direction with equal kinetic energy. If equal braking force is applied on both, then before coming to rest

1. A.$A$ will cover a greater distance
2. B.$B$ will cover a greater distance
3. C.both will cover the same distance
4. D.distance covered by them will depend on their respective velocities

A bullet is fired vertically up from a $400\mathrm{m}$ tall tower with a speed $80m/s$. If $g$ is taken as $10m/{\mathrm{s}}^2$, the time taken by the bullet to reach the ground will be

1. A.$8\mathrm{s}$
2. B.$16\mathrm{s}$
3. C.$20\mathrm{s}$
4. D.$24\mathrm{s}$

A cyclotron accelerates particles of mass $m$ and charge $q$. The energy of particles emerging is proportional to

1. A.$q^2/m$
2. B.$q/m^2$
3. C.$q^2/m^2$
4. D.$q$

The electric field inside a perfectly conducting hollow object is

1. A.$4\pi$
2. B.infinite
3. C.zero
4. D.dependent upon the shape of the object

A particle is moving with uniform acceleration along a straight line ABC, where AB = BC. The average velocity of the particle from A to B is 10 m/s and from B to C is 15 m/s. The average velocity for the whole journey from A to C in m/s is

1. A.12
2. B.12.5
3. C.13
4. D.13.5

The dimension of ‘impulse’ is the same as that of

1. A.pressure
2. B.angular momentum
3. C.work
4. D.linear momentum

A thermodynamic process where no heat is exchanged with the surroundings is

1. A.isothermal
2. B.adiabatic
3. C.isobaric
4. D.isotropic

Heat given to a body which raises its temperature by 1 °C is known as

1. A.water equivalent
2. B.thermal capacity
3. C.specific heat
4. D.temperature gradient

How many grams of $\mathrm{MgC}{\mathrm{O}}_3$ contain $24.00\mathrm{g}$ of oxygen? (The molar mass of $\mathrm{MgC}{\mathrm{O}}_3$ is $84.30\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$)

1. A.$42.15\mathrm{g}$
2. B.$84.30\mathrm{g}$
3. C.$126.00\mathrm{g}$
4. D.$154.00\mathrm{g}$

Consider the following statements : 1. Carbohydrates are the only source of energy to humans. 2. Fats give maximum energy on oxidation as compared to other foods. Which of the statements given above is/are correct?

1. A.1 only
2. B.2 only
3. C.Both 1 and 2
4. D.Neither 1 nor 2

Presbyopia is a visual defect caused by

1. A.Elongation of the eye ball.
2. B.Shortened curvature of the eye lens.
3. C.Weakening of the ciliary muscles.
4. D.Gradually increasing flexibility of the eye lens.

A beautiful rainbow on the sky is due to the

1. A.dispersion of sunlight from a water droplet only.
2. B.reflection of sunlight from a water droplet only.
3. C.reflection and refraction of sunlight from a water droplet only.
4. D.refraction, dispersion and reflection of sunlight from a water droplet.

MCQ (More than One Correct Answer) The weight of an object may be assigned by using Newton's

1. A.first law of motion.
2. B.second law of motion.
3. C.third law of motion.
4. D.laws of gravitation.

A current of 0.5 A is drawn by a filament of an electric bulb for 20 minutes. The amount of electric charge that flows through the circuit is

1. A.1 C
2. B.10 C
3. C.600 C
4. D.300 C

Which one among the following properties of a proton may change while it moves freely in a magnetic field?

1. A.Speed
2. B.Charge
3. C.Mass
4. D.Velocity

Power required by a boy of mass $30\mathrm{kg}$ to run up a staircase of 40 steps in 10 seconds is (Height of each step is $15\mathrm{cm}$) (Take $g=10m/{\mathrm{s}}^2$)

1. A.1800 Watt
2. B.180 Watt
3. C.18000 Watt
4. D.18 Watt