Railway Science (Physics-Heat and Thermodynamics)

Total Questions: 30

11. Why do particles in liquid water at 0°C have more energy than particles in ice at the same temperature? [RRB Group D 16/10/2018 (Afternoon)]

Correct Answer: (d) Because ice particles absorb heat energy during the process of transformation from ice to liquid water.
Solution:

When ice melts to become water, the process is known as fusion. During fusion, the ice absorbs heat energy from its surroundings without a change in temperature. This absorbed energy is used to break the bonds holding the ice crystals together, which increases the potential energy of the water molecules. Therefore, particles in liquid water at 0°C have more energy than particles in ice at the same temperature.

12. According to Joule's law of heat, the heat generated in a circuit depends on some factors. Which of the following can be blamed in this? [RRB Group D 1/11/2018 (Afternoon)]

Correct Answer: (b) Current, resistance of the conductor and time period for current to flow in it.
Solution:

According to Joule's law of heating, the heat produced in the wire is directly proportional to the square of the current, resistance of the wire, and time for which the current flows through the circuit. So, H = I²RT.

13. The 37° C temperature is equal to nearly: [RRB NTPC CBT - II (13/06/2022) Shift 1]

Correct Answer: (b) 98.6°F
Solution:

98.6° F. Relation between celsius (°C) and Fahrenheit (°F) : °C
= (°F − 32) × 5/9
37 = (F° - 32) × 5/9
37 × 9/5 = (F° - 32)
66.6 + 32 = F° ⇒ 98.6° = F°

14. -273.15°𝐶 temperature is equal to: [RRB NTPC CBT - I (15/03/2021) Evening]

Correct Answer: (d) 0 K
Solution:

0 K. The kelvin (symbol: K) is the base unit of thermodynamic temperature in the International System of Units (SI). To convert from Celsius to Kelvin, we use the formula: K = C + 273.15. In this case, we are given that the temperature is -273.15°𝐶. Putting this into the formula, we get: K = -273.15 +273.15 ⇒ K = 0

15. - 200° Celsius = ______ Fahrenheit [RRB ALP Tier - II (21/01/2019) Afternoon]

Correct Answer: (b) -328°
Solution:

Given, C = − 200°C Formula to convert Celsius into
Fahrenheit,

16. Select the most appropriate option. [RRB Group D 23/09/2018 (Morning)]

Correct Answer: (c) 32
Solution:

∵ F = 9/5  °C + 32. Given that the temperature is 0°C so, F = 9/5 (0) +32
⇒ F = 32.

17. The value of 100°C on the Kelvin scale is- [RRB Group D 27/09/2018 (Afternoon)]

Correct Answer: (c) 373 K
Solution:

373 K. The temperature in Kelvin (K) is equal to the temperature in degrees celsius (ºC) plus 273.15. The Celsius scale is a temperature scale introduced by Anders Celsius. The Kelvin scale is a temperature scale introduced by Lord Kelvin in 1848. 0°C celsius is also equal to 32 fahrenheit.

18. What is the standard room temperature in Kelvin? [RRB ALP Tier - I (21/08/2018) Evening]

Correct Answer: (b) 293K
Solution:

The Standard room temperature in Celsius is 27°. Conversion from Celsius to Kelvin : K = 273.15 + C.
Conversion from Fahrenheit to Celsius :
(F-32) × 5 /9 = C.

19. Which branch of physics deals with properties of fluids at rest? [RRB NTPC CBT - I (04/01/2021) Morning]

Correct Answer: (c) Hydrostatics
Solution:

Hydrostatics: Particularly with the pressure in a fluid or exerted by a fluid (gas or liquid) on an immersed body. Optics: The branch of physics that studies the behavior and properties of light. Thermodynamics: The branch of physics that deals with the relationships between heat and other forms of energy. Astrophysics: The branch of physics that deals with the physical properties of celestial objects.

20. Kerosene oil rises up in a wick of lantern because of: [RRB NTPC CBT - I (11/01/2021) Morning]

Correct Answer: (b) Capillarity
Solution:

The phenomenon of liquids rising or being drawn into narrow spaces or tubes against the force of gravity. Diffusion: The movement of molecules from an area of higher concentration to an area of lower concentration. Example - A tea bag immersed in a cup of hot water will diffuse into the water and change its colour. Osmosis: The movement of solvent molecules (usually water) through a semipermeable membrane from a region of lower solute concentration to higher solute concentration. Example - absorption of water from the soil.