Heat MCQs (421–450) with Answers and Explanations help students practice objective questions on calorimetry, latent heat, thermal expansion, and heat transfer applications.
This MCQ set is useful for school and competitive exams to revise Heat chapter fundamentals with quick explanations for better understanding.
421. The SI unit of heat energy is:
Correct Answer: B
Joule (J) is the SI unit of heat and energy.
422. One calorie is approximately equal to:
Correct Answer: C
1 calorie is approximately equal to 4.186 joules.
423. The heat required to raise the temperature of a body by 1°C is called:
Correct Answer: D
Heat capacity is the heat needed to raise temperature by 1°C.
424. The relation between heat capacity (C) and specific heat (c) is:
Correct Answer: A
Heat capacity equals mass times specific heat (C = m × c).
425. If specific heat of a substance is low, then it:
Correct Answer: B
Low specific heat means less heat is needed for the same temperature rise.
426. The specific heat of water is high, so water is used as:
Correct Answer: C
Water absorbs large heat without much temperature rise, acting as a coolant.
427. The unit of heat capacity is:
Correct Answer: B
Heat capacity is energy per unit temperature change (J/K).
428. The latent heat of fusion is the heat required to change:
Correct Answer: A
Fusion refers to melting (solid changing into liquid).
429. The latent heat of vaporization is the heat required to change:
Correct Answer: C
Vaporization means liquid changing into gas.
430. The SI unit of latent heat is:
Correct Answer: D
Latent heat is heat per unit mass, measured in J/kg.
431. During melting, temperature remains constant because:
Correct Answer: B
Heat energy is used to change state, not to increase temperature.
432. During boiling, temperature remains constant because:
Correct Answer: C
Supplied heat is used for change of state at constant temperature.
433. Which mode of heat transfer is mainly responsible for heating a room by a heater?
Correct Answer: B
Hot air rises and circulates, warming the room by convection.
434. A thermos flask reduces heat loss mainly by:
Correct Answer: D
Vacuum prevents conduction and convection, coating reduces radiation.
435. Black clothes are preferred in winter because they:
Correct Answer: B
Black surfaces absorb maximum radiant heat.
436. White clothes are preferred in summer because they:
Correct Answer: C
White surfaces reflect radiant heat and keep the body cooler.
437. The heat transfer through vacuum from Sun to Earth occurs by:
Correct Answer: D
Radiation does not need any medium to transfer heat.
438. The heat transfer along a metal spoon kept in hot tea is mainly by:
Correct Answer: A
In solids like metals, heat passes by conduction.
439. The transfer of heat that involves movement of particles is:
Correct Answer: B
Convection happens due to bulk movement of fluid particles.
440. The process of changing liquid into vapour below its boiling point is called:
Correct Answer: D
Evaporation happens at the surface below boiling point.
441. Evaporation increases when the surface area is:
Correct Answer: C
Larger surface area exposes more molecules for evaporation.
442. Evaporation decreases when humidity is:
Correct Answer: A
High humidity slows evaporation as air already contains water vapour.
443. Sweating cools the body because:
Correct Answer: B
Evaporation of sweat absorbs latent heat from the body, cooling it.
444. The SI unit of thermal conductivity is:
Correct Answer: D
Thermal conductivity is measured in watts per meter-kelvin (W/mK).
445. The coefficient of linear expansion is measured in:
Correct Answer: C
Expansion coefficient is defined per degree temperature change (K⁻¹).
446. The coefficient of volume expansion of a solid is approximately:
Correct Answer: A
For isotropic solids, β ≈ 3α.
447. The coefficient of areal expansion is approximately:
Correct Answer: B
For isotropic solids, areal expansion coefficient ≈ 2α.
448. A thermostat works on the principle of:
Correct Answer: C
Thermostats use bimetallic strips which expand differently.
449. The temperature of absolute zero in Celsius scale is approximately:
Correct Answer: D
Absolute zero is about −273°C (0 K).
450. The process of changing gas into liquid is called:
Correct Answer: B
Condensation converts gas (vapour) into liquid.
Heat MCQs (421–450) FAQs
1. What topics are covered in Heat MCQs (421–450)?
This set includes calorimetry basics, heat capacity, specific heat, latent heat, evaporation, and thermal expansion formulas.
2. Are these Heat MCQs helpful for school exams and competitive exams?
Yes, these questions are useful for objective practice and quick revision of Heat chapter concepts.
3. Do these Heat MCQs provide explanations for answers?
Yes, each question includes the correct option with a short explanation for clarity.
4. How do Heat MCQs improve concept understanding?
Practicing MCQs helps identify weak areas and improves recall of formulas and definitions.
5. What should be revised after completing this Heat MCQ set?
Revise thermal expansion relations, latent heat definitions, and evaporation factors for stronger fundamentals.
This set includes calorimetry basics, heat capacity, specific heat, latent heat, evaporation, and thermal expansion formulas.
2. Are these Heat MCQs helpful for school exams and competitive exams?
Yes, these questions are useful for objective practice and quick revision of Heat chapter concepts.
3. Do these Heat MCQs provide explanations for answers?
Yes, each question includes the correct option with a short explanation for clarity.
4. How do Heat MCQs improve concept understanding?
Practicing MCQs helps identify weak areas and improves recall of formulas and definitions.
5. What should be revised after completing this Heat MCQ set?
Revise thermal expansion relations, latent heat definitions, and evaporation factors for stronger fundamentals.
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