Q1. What is meant by transfer of heat?
A) Production of heat
B) Flow of heat from hot body to cold body
C) Destruction of heat
D) Conversion of heat into light
Answer: B
Q2. Heat is transferred from a body at higher temperature to a body at:
A) Same temperature
B) Lower temperature
C) Infinite temperature
D) Zero temperature
Answer: B
Q3. Which of the following is not a mode of heat transfer?
A) Conduction
B) Convection
C) Radiation
D) Reflection
Answer: D
Q4. Heat transfer through solids mainly occurs by:
A) Convection
B) Radiation
C) Conduction
D) Evaporation
Answer: C
Q5. Heat transfer in liquids and gases mainly takes place by:
A) Conduction
B) Convection
C) Radiation
D) Reflection
Answer: B
Q6. Heat from the Sun reaches the Earth by:
A) Conduction
B) Convection
C) Radiation
D) Diffusion
Answer: C
Q7. Which material is a good conductor of heat?
A) Wood
B) Glass
C) Copper
D) Plastic
Answer: C
Q8. Which material is a poor conductor of heat?
A) Iron
B) Aluminium
C) Silver
D) Rubber
Answer: D
Q9. Woolen clothes keep us warm because they:
A) Produce heat
B) Contain air which is a bad conductor
C) Reflect sunlight
D) Absorb moisture
Answer: B
Q10. Metals are good conductors because they contain:
A) Molecules
B) Free electrons
C) Protons
D) Neutrons
Answer: B
Q11. Which of the following is an insulator?
A) Copper
B) Iron
C) Wood
D) Silver
Answer: C
Q12. The SI unit of thermal conductivity is:
A) J
B) W m⁻¹ K⁻¹
C) kg
D) N
Answer: B
Q13. The process of heat transfer without a material medium is called:
A) Conduction
B) Convection
C) Radiation
D) Fusion
Answer: C
Q14. Sea breeze occurs during:
A) Night
B) Day
C) Winter only
D) Rainy season
Answer: B
Q15. Land breeze occurs during:
A) Day
B) Afternoon
C) Night
D) Summer only
Answer: C
Q16. Hot air rises because it becomes:
A) Denser
B) Lighter
C) Heavier
D) Colder
Answer: B
Q17. Which color is the best absorber of heat?
A) White
B) Silver
C) Black
D) Yellow
Answer: C
Q18. Which color is the best reflector of heat?
A) Black
B) White
C) Red
D) Blue
Answer: B
Q19. Vacuum flask prevents heat transfer mainly by reducing:
A) Radiation only
B) Conduction and convection
C) Convection only
D) Conduction only
Answer: B
Q20. Which part of a thermos bottle is silvered?
A) Outer surface only
B) Inner surface only
C) Both surfaces facing vacuum
D) Bottom only
Answer: C
Q21. The transfer of heat by actual movement of particles is called:
A) Radiation
B) Conduction
C) Convection
D) Reflection
Answer: C
Q22. Which of the following occurs in vacuum?
A) Conduction only
B) Convection only
C) Radiation only
D) Conduction and convection
Answer: C
Q23. Cooking utensils are generally made of:
A) Wood
B) Copper or aluminium
C) Plastic
D) Rubber
Answer: B
Q24. Wooden handles are used in cooking pots because wood is:
A) A conductor
B) A bad conductor
C) A radiator
D) A reflector
Answer: B
Q25. Which metal has the highest thermal conductivity?
A) Iron
B) Copper
C) Silver
D) Lead
Answer: C
Q26. Why are roofs painted white in hot regions?
A) To absorb heat
B) To reflect heat radiation
C) To produce heat
D) To increase conduction
Answer: B
Q27. Heat transfer through electromagnetic waves is called:
A) Conduction
B) Radiation
C) Convection
D) Evaporation
Answer: B
Q28. The unit of heat is:
A) Joule
B) Watt
C) Newton
D) Kelvin
Answer: A
Q29. Which substance is a poor conductor of heat?
A) Aluminium
B) Copper
C) Air
D) Silver
Answer: C
Q30. In convection currents, hot fluid moves:
A) Downward
B) Sideways only
C) Upward
D) Nowhere
Answer: C
Numerical and Formula-Based MCQs
Q31. If 500 J of heat is transferred in 10 s, the rate of heat transfer is:
A) 5 W
B) 50 W
C) 5000 W
D) 100 W
Answer: B
Q32. Power = Heat transferred / ?
A) Mass
B) Temperature
C) Time
D) Volume
Answer: C
Q33. If 1000 J of heat flows in 20 s, the power is:
A) 20 W
B) 50 W
C) 100 W
D) 200 W
Answer: B
Q34. A heater transfers 2400 J in 60 s. Its power is:
A) 20 W
B) 30 W
C) 40 W
D) 50 W
Answer: C
Q35. If a body receives 600 J in 12 s, rate of heat transfer equals:
A) 30 W
B) 40 W
C) 50 W
D) 60 W
Answer: C
Q36. Thermal conductivity is represented by:
A) c
B) k
C) l
D) m
Answer: B
Q37. Heat transfer by conduction depends upon:
A) Thermal conductivity
B) Area
C) Temperature difference
D) All of these
Answer: D
Q38. A black surface is a good:
A) Absorber and emitter
B) Reflector only
C) Conductor
D) Insulator
Answer: A
Q39. The shiny surface of a thermos bottle reduces:
A) Conduction
B) Convection
C) Radiation
D) Evaporation
Answer: C
Q40. Which mode of heat transfer is fastest in vacuum?
A) Conduction
B) Convection
C) Radiation
D) Diffusion
Answer: C
Q41. Heat always flows from:
A) Cold body to hot body
B) Hot body to cold body
C) Equal temperatures
D) None of these
Answer: B
Q42. Which gas is commonly present in the vacuum space of a thermos bottle?
A) Oxygen
B) Nitrogen
C) Hydrogen
D) No gas (vacuum)
Answer: D
Q43. A metal spoon placed in hot tea becomes hot due to:
A) Radiation
B) Conduction
C) Convection
D) Reflection
Answer: B
Q44. Convection currents cannot occur in:
A) Water
B) Air
C) Vacuum
D) Oil
Answer: C
Q45. Which of the following is the best radiator?
A) Polished silver surface
B) Black rough surface
C) White polished surface
D) Transparent surface
Answer: B
Q46. Heat transfer through solids is due to:
A) Free movement of liquid
B) Molecular vibrations and free electrons
C) Wind currents
D) Vacuum
Answer: B
Q47. A room heater warms a room mainly by:
A) Convection
B) Radiation only
C) Conduction
D) Diffusion
Answer: A
Q48. The handle of an electric iron is made of plastic because plastic is:
A) Good conductor
B) Poor conductor
C) Good absorber
D) Metal
Answer: B
Q49. Which material is used in thermos bottle stoppers?
A) Iron
B) Copper
C) Cork or plastic
D) Silver
Answer: C
Q50. Which statement is correct?
A) Radiation needs a medium
B) Conduction occurs only in gases
C) Convection occurs due to movement of particles
D) Heat flows from cold to hot body
Answer:C
Q51. The process by which heat travels through a material without movement of matter is called:
A) Convection
B) Radiation
C) Conduction
D) Evaporation
Answer: C
Q52. Which medium is necessary for conduction?
A) Vacuum
B) Material medium
C) Empty space
D) None of these
Answer: B
Q53. The transfer of heat in gases mainly takes place by:
A) Radiation
B) Conduction
C) Convection
D) Reflection
Answer: C
Q54. Which one is the poorest conductor among the following?
A) Silver
B) Copper
C) Air
D) Aluminium
Answer: C
Q55. Why are double-glazed windows used in cold countries?
A) To increase radiation
B) To reduce heat loss by conduction
C) To absorb heat
D) To increase convection
Answer: B
Q56. Which surface is the poorest absorber of heat radiation?
A) Black rough
B) White rough
C) Polished silver
D) Black dull
Answer: C
Q57. The process responsible for boiling water in a kettle is mainly:
A) Conduction
B) Radiation
C) Convection
D) Reflection
Answer: C
Q58. The SI unit of power is:
A) Joule
B) Newton
C) Watt
D) Kelvin
Answer: C
Q59. Heat transfer by radiation takes place in the form of:
A) Sound waves
B) Electromagnetic waves
C) Water waves
D) Mechanical waves
Answer: B
Q60. Why do birds fluff up their feathers in winter?
A) To absorb more heat
B) To trap air and reduce heat loss
C) To increase radiation
D) To increase convection
Answer: B
Numerical and Formula-Based MCQs
Q61. A heater supplies 1800 J of heat in 30 s. Its power is:
A) 30 W
B) 60 W
C) 90 W
D) 120 W
Answer: B
Q62. If a body gains 4000 J in 80 s, the rate of heat transfer is:
A) 25 W
B) 40 W
C) 50 W
D) 80 W
Answer: C
Q63. A device has power 100 W. In 20 s it transfers heat equal to:
A) 1000 J
B) 1500 J
C) 2000 J
D) 2500 J
Answer: C
Q64. Heat transferred = Power × ?
A) Area
B) Volume
C) Time
D) Density
Answer: C
Q65. If power is 50 W and time is 40 s, heat transferred is:
A) 1000 J
B) 1500 J
C) 2000 J
D) 2500 J
Answer: C
Q66. Which factor does not affect conduction?
A) Temperature difference
B) Cross-sectional area
C) Nature of material
D) Color of material
Answer: D
Q67. The handle of a saucepan is usually made of Bakelite because it is:
A) A good conductor
B) A poor conductor
C) A radiator
D) A reflector
Answer: B
Q68. Which of the following is a good insulator?
A) Steel
B) Copper
C) Cork
D) Aluminium
Answer: C
Q69. Which type of surface emits heat most effectively?
A) White shiny
B) Black dull
C) Polished silver
D) Transparent
Answer: B
Q70. Radiation can travel through:
A) Solids only
B) Liquids only
C) Gases only
D) Vacuum
Answer: D
Q71. A room heater placed near the floor warms the whole room because of:
A) Conduction
B) Radiation
C) Convection currents
D) Reflection
Answer: C
Q72. Which of the following is used as a heat insulator in refrigerators?
A) Iron
B) Glass wool
C) Copper
D) Silver
Answer: B
Q73. Which surface reflects heat radiation the most?
A) Black rough
B) White rough
C) Polished silver
D) Black dull
Answer: C
Q74. Sea breeze blows from:
A) Land to sea
B) Sea to land
C) East to west
D) North to south
Answer: B
Q75. Land breeze blows from:
A) Sea to land
B) Land to sea
C) North to south
D) South to north
Answer: B
Q76. Which mode of heat transfer requires no medium?
A) Conduction
B) Convection
C) Radiation
D) Evaporation
Answer: C
Q77. Which material is used between the walls of a thermos flask?
A) Air
B) Water
C) Vacuum
D) Mercury
Answer: C
Q78. Why are deserts hot during the day and cold at night?
A) Sand is a poor absorber
B) Sand radiates heat rapidly
C) Air is absent
D) Water is present
Answer: B
Q79. The unit W m⁻¹ K⁻¹ belongs to:
A) Specific heat capacity
B) Thermal conductivity
C) Latent heat
D) Density
Answer: B
Q80. A shiny teapot loses heat mainly by reducing:
A) Conduction
B) Convection
C) Radiation
D) Evaporation
Answer: C
More Numerical MCQs
Q81. A heater of power 200 W operates for 15 s. Heat supplied is:
A) 1500 J
B) 2000 J
C) 3000 J
D) 4000 J
Answer: C
Q82. If 6000 J is transferred in 2 minutes, the power is:
A) 25 W
B) 50 W
C) 75 W
D) 100 W
Answer: B
Q83. A 120 W heater works for 10 s. Heat produced is:
A) 600 J
B) 1000 J
C) 1200 J
D) 2400 J
Answer: C
Q84. A heater transfers 7200 J in 90 s. Power is:
A) 60 W
B) 70 W
C) 80 W
D) 90 W
Answer: C
Q85. Heat transfer through a copper rod is an example of:
A) Radiation
B) Conduction
C) Convection
D) Diffusion
Answer: B
Q86. Which liquid is commonly used in hot water bottles because it stores heat effectively?
A) Alcohol
B) Petrol
C) Water
D) Mercury
Answer: C
Q87. Which of the following is not a conductor?
A) Silver
B) Iron
C) Plastic
D) Aluminium
Answer: C
Q88. Black clothes are preferred in winter because they:
A) Reflect heat
B) Absorb more heat
C) Produce heat
D) Reduce radiation
Answer: B
Q89. White clothes are preferred in summer because they:
A) Absorb heat
B) Conduct heat
C) Reflect heat radiation
D) Produce heat
Answer: C
Q90. Which process causes smoke to rise up a chimney?
A) Conduction
B) Radiation
C) Convection
D) Reflection
Answer: C
Q91. In vacuum flasks, the stopper is usually made of:
A) Copper
B) Cork
C) Iron
D) Aluminium
Answer: B
Q92. Which heat transfer process takes place in solids without movement of particles?
A) Radiation
B) Convection
C) Conduction
D) Evaporation
Answer: C
Q93. Why are cooking pots made of aluminium?
A) It is an insulator
B) It is a poor conductor
C) It is a good conductor
D) It absorbs moisture
Answer: C
Q94. Which material is the best heat conductor?
A) Glass
B) Wood
C) Silver
D) Plastic
Answer: C
Q95. The rise of warm air and fall of cool air is called:
A) Radiation
B) Convection current
C) Reflection
D) Refraction
Answer: B
Q96. A vacuum flask minimizes heat transfer by:
A) Conduction only
B) Convection only
C) Radiation only
D) Conduction, convection and radiation
Answer: D
Q97. Which mode of heat transfer is responsible for warmth felt near a fire?
A) Conduction
B) Convection
C) Radiation
D) Evaporation
Answer: C
Q98. A heater with power 150 W works for 20 s. Heat supplied is:
A) 1500 J
B) 2000 J
C) 2500 J
D) 3000 J
Answer: D
Q99. If 9000 J of heat is transferred in 3 minutes, the power is:
A) 40 W
B) 50 W
C) 60 W
D) 70 W
Answer: B
Q100. Which statement about heat transfer is correct?
A) Convection occurs in vacuum.
B) Radiation needs a medium.
C) Heat naturally flows from higher temperature to lower temperature.
D) Conduction occurs only in gases.
Answer: C