Physics · NDA previous year questions

According to the New Cartesian Sign Convention, which one of the following is correct is respect of the formula $\frac{1}{f}=\frac{1}{v}+\frac{1}{u}$, where symbols have their usual meanings?

1. A.It applies only to spherical mirrors
2. B.It applies only to spherical lenses
3. C.It applies to spherical mirrors as well as spherical lenses
4. D.It is an invalid formula

Which one of the following statements is not correct for light rays?

1. A.Light travels at different speeds in different media
2. B.Light travels at almost 300 million metres per second in air
3. C.Light speeds down as it leaves a water surface and enters the air
4. D.Light speeds up as it leaves a glass surface and enters the air

A glass prism splits white light into different colours. This phenomenon is called dispersion of light by prism. Which one of the following statements is correct?

1. A.Red light will deviate the most and it is because of the reflection of light
2. B.Violet light will deviate the most and it is because of the refraction of light
3. C.Red light will deviate the most and it is because of the refraction of light
4. D.Violet light will deviate the most and it is because of the reflection of light

A current of 1.0 A is drawn by a filament of an electric bulb for 10 minutes. The amount of electric charge that flows through the circuit is

1. A.0.1 C
2. B.10 C
3. C.600 C
4. D.800 C

Which one of the following formulas does not represent electrical power?

1. A.$I^{2}R$
2. B.$I{R}^2$
3. C.$VI$
4. D.$V^2/R$

The sound created in a big hall persists because of the repeated reflections. The phenomenon is called

1. A.Reverberation
2. B.Dispersion
3. C.Refraction
4. D.Diffraction

Which of the following statements is NOT correct regarding the travel of sound waves ?

1. A.Sound waves can travel through water
2. B.Sound waves can travel through air
3. C.Sound waves can travel through steel
4. D.Sound waves can travel through vacuum

The correct relation between the radius of curvature $R$ and focal length $f$ of a spherical mirror is

1. A.$R=f$
2. B.$R=2f$
3. C.$R=3f$
4. D.$R=4f$

A lemon kept in water in a glass tumbler appears to be larger than its actual size. It is because of

1. A.reflection of light
2. B.scattering of light
3. C.refraction of light
4. D.polarization of light

Light enters the eye through a thin membrane called

1. A.retina
2. B.cornea
3. C.pupil
4. D.iris

Name the scientist who first used a glass prism to obtain the spectrum of sunlight

1. A.C. V. Raman
2. B.Lord Rayleigh
3. C.Isaac Newton
4. D.S. Chandrasekhar

The cost of energy to operate an industrial refrigerator that consumes 5 kW power working 10 hours per day for 30 days will be (Given that the charge per kW.h of energy = ₹ 4)

1. A.₹ 600
2. B.₹ 6,000
3. C.₹ 1,200
4. D.₹ 1,500

Which one of the following statements regarding magnetic field is NOT correct ?

1. A.Magnetic field is a quantity that has direction and magnitude
2. B.Magnetic field lines are closed curves
3. C.Magnetic field lines are open curves
4. D.No two magnetic field lines are found to cross each other

Two equal resistors R are connected in parallel, and a battery of 12 V is connected across this combination. A dc current of 100 mA flows through the circuit as shown below : The value of R is

1. A.120 Ω
2. B.240 Ω
3. C.60 Ω
4. D.100 Ω

Which one of the following is NOT the unit of energy ?

1. A.Joule
2. B.Watt-hr
3. C.Newton-metre
4. D.$\mathrm{kg}\text{-}metre/se{\mathrm{c}}^2$

Light of uniform intensity impinges perpendicularly on a totally reflecting surface. If the area of the surface is halved, the radiation force on it will become

1. A.double
2. B.half
3. C.four times
4. D.one fourth

Consider the following image : A proton enters a magnetic field at right angles to it, as shown above. The direction of force acting on the proton will be

1. A.to the right
2. B.to the left
3. C.out of the page
4. D.into the page

Which one of the following statements about sound is NOT correct ?

1. A.Sound travels at a speed slower than the speed of light
2. B.Sound waves are transverse waves
3. C.Sound waves are longitudinal waves
4. D.Sound travels faster in moist air than in dry air

When the short circuit condition occurs, the current in the circuit

1. A.becomes zero
2. B.remains constant
3. C.increases substantially
4. D.keeps on changing randomly

Which one of the following types of radiations has the smallest wave-length ?

1. A.Microwaves
2. B.Infra-red
3. C.Visible light
4. D.X-rays

The instrument used for detecting the presence of electric current in a circuit is

1. A.Refractometer
2. B.Galvanometer
3. C.Viscometer
4. D.Diffractometer

A lens has a power of $+2\cdot 0\text{Dioptre}$. Which one of the following statements about the lens is true ?

1. A.The lens is concave and has a focal length of $0\cdot 5\text{metre}$
2. B.The lens is convex and has a focal length of $2\cdot 0\text{metre}$
3. C.The lens is convex and has a focal length of $0\cdot 5\text{metre}$
4. D.The lens is concave and has a focal length of $2\cdot 0\text{metre}$

The refractive index of fused quartz is $1\cdot 46$ and that of sapphire is $1\cdot 77$. If $v_q$ is the speed of light in quartz and $v_s$ is the speed of light in sapphire, then which one of the following relations is correct ?

1. A.$v_q>v_s$
2. B.$v_s>v_q$
3. C.$v_s=v_q$
4. D.$v_s=\frac{v_q}{2}$

In case of a concave mirror, if an object is kept between principal focus F and pole P of the mirror, then which one of the following statements about the image is NOT correct ?

1. A.The image will be virtual
2. B.The image will be enlarged or magnified
3. C.The image will be formed at infinity
4. D.The image will be erect

A thin disc and a thin ring, both have mass M and radius R. Both rotate about axes through their center of mass and are perpendicular to their surfaces at the same angular velocity. Which of the following is true?

1. A.The ring has higher kinetic energy
2. B.The disc has higher kinetic energy
3. C.The ring and the disc have the same kinetic energy
4. D.Kinetic energies of both the bodies are zero since they are not in linear motion