Physics · NDA previous year questions

Which of the following statements about electromagnetic waves, sound waves and water waves is/are correct? 1. They exhibit reflection 2. They carry energy 3. They exert pressure 4. They can travel in vacuum Select the correct answer using the code given below :

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

Thermal capacity of a body depends on the

1. A.mass of the body only
2. B.mass and shape of the body only
3. C.density of the body
4. D.mass, shape and temperature of the body

Light year is a unit for measurement of

1. A.age of universe
2. B.very small time intervals
3. C.very high temperature
4. D.very large distance

Concave mirror is used in headlights of vehicles, because it

1. A.focuses light from the bulb onto nearby vehicles
2. B.sends parallel rays
3. C.fits well into the shape of the headlight
4. D.is cheaper than other mirrors

Which one of the following statements about energy is correct?

1. A.Energy can be created as well as destroyed.
2. B.Energy can be created but not destroyed.
3. C.Energy can neither be created nor destroyed.
4. D.Energy cannot be created but can be destroyed.

Step-up transformers are used for

1. A.increasing electrical power
2. B.decreasing electrical power
3. C.decreasing voltage
4. D.increasing voltage

Which one among the following waves carries the maximum energy per photon?

1. A.X-rays
2. B.Radio waves
3. C.Light waves
4. D.Microwaves

A rainbow is produced due to which one of the following phenomena?

1. A.Dispersion of light
2. B.Interference of light
3. C.Diffraction of light
4. D.Scattering of light by atmospheric dust

Bats detect obstacles in their path by receiving the reflected

1. A.Infrasonic waves
2. B.Ultrasonic waves
3. C.Radio waves
4. D.Microwaves

The statement that ‘heat cannot flow by itself from a body at a lower temperature to a body at a higher temperature’, is known as

1. A.Zeroth law of thermodynamics
2. B.First law of thermodynamics
3. C.Second law of thermodynamics
4. D.Third law of thermodynamics

Which one of the following waves does not belong to the category of the other three?

1. A.X-rays
2. B.Microwaves
3. C.Radio waves
4. D.Sound waves

Which one of the following statements is not correct?

1. A.Ultrasonic waves cannot get reflected, refracted or absorbed.
2. B.Ultrasonic waves are used to detect the presence of defects like cracks, porosity, etc. in the internal structure of common structure materials.
3. C.Ultrasonic waves can be used for making holes in very hard materials like diamond.
4. D.Ultrasonic waves cannot travel through vacuum.

An object moves in a circular path with a constant speed. Which one of the following statements is correct?

1. A.The centripetal acceleration of the object is smaller for a gentle curve (i.e., curve of larger radius) than that for a sharp curve (i.e., curve of smaller radius).
2. B.The centripetal acceleration is greater for a gentle curve than that for a sharp curve.
3. C.The centripetal acceleration is the same for both, the gentle and sharp curves.
4. D.The centripetal acceleration causes the object to slow down.

The force acting on a particle of mass $m$ moving along the $x$-axis is given by $F(x)=A{x}^2-Bx$. Which one of the following is the potential energy of the particle?

1. A.$2Ax-B$
2. B.$-\frac{x^2}{6}(2Ax-3B)$
3. C.$A{x}^3-B{x}^2$
4. D.Zero

How long does light take to reach the Earth from the Sun?

1. A.About 4 minutes
2. B.About 8 minutes
3. C.About 24 minutes
4. D.About 24 hours

The mirrors used as rear-view mirrors in vehicles are

1. A.concave
2. B.convex
3. C.cylindrical
4. D.plane

Which one of the following waves is used for detecting forgery in currency notes?

1. A.Ultraviolet waves
2. B.Infrared waves
3. C.Radio waves
4. D.Microwaves

Water boils at a lower temperature at high altitudes, because

1. A.the air pressure is less
2. B.outside temperature is less
3. C.latent heat is less
4. D.None of the above

Melanin is the natural pigment that gives colour to human skin, hair and the iris. It provides protection against

1. A.Ultraviolet radiation
2. B.Infrared radiation
3. C.X-ray radiation
4. D.Short wave radio radiation

Which one of the following statements about a satellite orbiting around the Earth is correct?

1. A.Satellite is kept in orbit by remote control from ground station.
2. B.Satellite is kept in orbit by retro-rocket and solar energy keeps it moving around the Earth.
3. C.Satellite requires energy from solar panels and solid fuels for orbiting.
4. D.Satellite does not require any energy for orbiting.

Light year is a measure of

1. A.time
2. B.distance
3. C.total amount of light falling on the Earth in a year
4. D.average intensity of light falling on the Earth in a year

The speed of a car travelling on a straight road is listed below at successive intervals of $1\text{ s}$ : | Time (s) | 0 | 1 | 2 | 3 | 4 | | :--- | :--- | :--- | :--- | :--- | :--- | | Speed (m/s) | 0 | 2 | 4 | 6 | 8 | Which of the following is/are correct ? The car travels 1. with a uniform acceleration of $2{\text{ m/s}}^2$. 2. $16\text{ m}$ in $4\text{ s}$. 3. with an average speed of $4\text{ m/s}$. Select the correct answer using the code given below :

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

The speed of a body that has Mach number more than 1 is

1. A.supersonic
2. B.subsonic
3. C.300 m/s
4. D.about 10 m/s

The following figure shows displacement versus time curve for a particle executing simple harmonic motion : Which one of the following statements is correct ?

1. A.Phase of the oscillating particle is same at $t=1$ s and $t=3$ s
2. B.Phase of the oscillating particle is same at $t=2$ s and $t=8$ s
3. C.Phase of the oscillating particle is same at $t=3$ s and $t=7$ s
4. D.Phase of the oscillating particle is same at $t=4$ s and $t=10$ s

A circular coil of single turn has a resistance of $20\Omega$. Which one of the following is the correct value for the resistance between the ends of any diameter of the coil ?

1. A.$5\Omega$
2. B.$10\Omega$
3. C.$20\Omega$
4. D.$40\Omega$