Part – B General knowledge (English) (NDA/NA SOLVED PAPER 2019 (I) (101 to 150)

Total Questions: 50

11. The sun is seen little before it rises and for a short while after it sets. This is because of:

Correct Answer: (b) atmospheric refraction
Solution:

The sun is seen little before it rises and for short while after it sets due to atmospheric refraction. When light enters from vacuum to earth’s atmosphere, it basically enters from rarer to denser medium and bends towards horizon. During sunrise, when the sun is just below the horizon, our atmosphere causes the light rays to bend and we see the sun early.
Similarly, at sunset, the apparent position of the sun is visible to us and not the actual position due to the same bending of light rays effect.

12. The figure shown below gives the time (t) versus position (x) graph of three objects A, B and C. Which one of the following is the correct relation between their speeds Vᴀ, Vʙ and Vᴄ, respectively at any instant (t > 0)

Correct Answer: (b) Vᴀ > Vʙ > Vᴄ
Solution:

13. 1 dyne (a unit of force in CGS system) equals to:

Correct Answer: (d) 10⁻⁵ kg-m/s²
Solution:

14. In the given velocity (v) versus time (t) graph, accelerated and decelerated motions are respectively represented by line segments:

Correct Answer: (c) CD and AB
Solution:

15. Which one of the following statement regarding a thermo flask is not correct?

Correct Answer: (c) The surface of inner wall radiates good amount of heat and the surface of outer wall absorbs some of the heat that is radiated from the inner wall.
Solution:

The thermo flask has the silver coating on the inner surface which prevents heat transfer by radiation. The vacuum between its double wall prevents heat moving by convection. The thinness of  the glass walls stops heat entering or leaving the flask by conduction. Hence, option (c) is not a correct statement regarding a thermo flask.

16. Black hole is a:

Correct Answer: (c) star which has collapsed into itself and has large acceleration due to gravity on its surface
Solution:

A black hole is a star which has collapsed into itself and has large acceleration due to gravity on its surface. A black hole forms when the center of a very massive star collapses in upon itself.
The region in space of a black-hole, the pulling force of gravity is, so strong that light is not able to escape.

17. The formula for conversion between Fahrenheit and Celsius is °F = X + (1.8 × °C)?

Correct Answer: (a) 32
Solution:

18. When a beam of white light passes through a glass prism, the colour of light beam that deviates the least is:

Correct Answer: (b) red
Solution:

The wavelength of red colour of light is maximum, therefore when a beam of white light passes through a glass prism, then the light of red colour deviates the least.

19. LIGO stands for:

Correct Answer: (a) Laser Interferometer Gravitational wave Observatory
Solution:

LIGO stands for Laser Interferometer Gravitational wave Observatory. It is a large scale physics experiment and observatory to detect cosmic gravitational waves and to develop gravitational waves observations as an astronomical tool.

20. A fuse wire must be:

Correct Answer: (a) conducting and of low melting point
Solution:

Fuse wire should have high resistance and low melting point. It is because when high current pass through the circuit, at first, it will resist the high current.
A fuse wire protects our electric appliances from damaging due to sudden increase in electric current.