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Heat

179 MCQ questions with answers and explanations · page 1 of 8

Test yourself▶ 25 question test▶ 50 question test

Q1. When an object is heated, its molecules-

  1. Awill increase the speed of
  2. Bwill reduce the energy of
  3. Cwill increase the weight of
  4. Dwill reduce the weight of
Show answer & explanation

Answer: A) will increase the speed of

Q2. What does the temperature of an object indicate?

  1. Athe total energy of its molecules
  2. Bthe average energy of its molecules
  3. Cthe total velocity of its molecules
  4. DThe average kinetic energy of its molecules
Show answer & explanation

Answer: D) The average kinetic energy of its molecules

Q3. The temperature of an object indicates that on contact the heat-

  1. Awill flow from that object to an object at a higher temperature
  2. Bflow from an object of relatively lower temperature to that object
  3. Cflow from that object to the earth
  4. Dflow from the Earth to that object
Show answer & explanation

Answer: B) flow from an object of relatively lower temperature to that object

Q4. An increase in the temperature of an object means that the object's-

  1. Akinetic energy has increased
  2. BThe potential energy has increased.
  3. Cmechanical energy has increased
  4. DThermal energy has increased.
Show answer & explanation

Answer: D) Thermal energy has increased.

Q5. When an object is cooled, its molecules-

  1. Aincreases the energy of
  2. Bincreases the energy of
  3. Cincreases the mass of
  4. Dincreases the weight of
Show answer & explanation

Answer: B) increases the energy of

Q6. Heat is a form of energy that can be converted into work. Who first provided direct evidence of this?

  1. ADavy
  2. BRumford
  3. CCelsius
  4. DFahrenheit
Show answer & explanation

Answer: B) Rumford

Q7. Which scientist first melted two pieces of ice by rubbing them together?

  1. ARumford
  2. BJoule
  3. CDavy
  4. DCelsius
Show answer & explanation

Answer: C) Davy

Q8. Whenever work is converted into heat or heat is converted into work, the ratio of the work done to the heat produced is a constant, called the mechanical equivalent of heat. Its value is

  1. A4186 joules/kcal
  2. B4.186x107 erg/calorie
  3. C4.186 joules/calorie
  4. DAll of the above
Show answer & explanation

Answer: D) All of the above

Q9. Which of the following is correct?

  1. AW/Q=J
  2. BW×Q=J
  3. CQ/W=J
  4. DJ/Q=W
Show answer & explanation

Answer: A) W/Q=J

Q10. When some water is continuously churned, its temperature increases. In this process-

  1. AHeat energy is converted into thermal energy.
  2. BThermal energy is converted into heat energy.
  3. Cmechanical energy is converted into thermal energy
  4. Dthermal energy is converted into mechanical energy
Show answer & explanation

Answer: C) mechanical energy is converted into thermal energy

Q11. The temperature of boiling water in a steam engine can be high due to what reason?

  1. Asubstances dissolved in water
  2. BThere is low pressure inside the boiler.
  3. CThere is high pressure inside the boiler
  4. DFire occurs at extremely high temperatures
Show answer & explanation

Answer: C) There is high pressure inside the boiler

Q12. The water from the hand pump is hot in winter because-

  1. AIn winter our body is cold, hence water appears warm.
  2. BThe temperature inside the Earth is higher than the temperature in the atmosphere
  3. CThe pumping action creates friction, which heats the water.
  4. DWater from inside comes out and absorbs heat from the surroundings
Show answer & explanation

Answer: B) The temperature inside the Earth is higher than the temperature in the atmosphere

Q13. The unit of temperature in the SI system is-

  1. AKelvin
  2. BDegree Celsius
  3. Cdegree centigrade
  4. Ddegrees Fahrenheit
Show answer & explanation

Answer: A) Kelvin

Q14. Which of the following is not a unit of heat?

  1. ACalories
  2. Bkilocalories
  3. CJoule
  4. DDegree Celsius
Show answer & explanation

Answer: D) Degree Celsius

Q15. The SI unit of temperature is-

  1. AKelvin
  2. BCelsius
  3. Ccentigrade
  4. DFahrenheit
Show answer & explanation

Answer: A) Kelvin

Q16. The value of 1 kilocalorie of heat is-

  1. A4.2 joules
  2. B4.2 x 102 joules
  3. C4.2 x 10 joules
  4. D4.2 x 10 joules
Show answer & explanation

Answer: C) 4.2 x 10 joules

Q17. The reason for the water temperature being higher at the bottom of the waterfall than at the top is-

  1. AWater has more potential energy at the bottom
  2. BProvides surface heat to the ground surface
  3. CThe kinetic energy of falling water is converted into heat.
  4. DFalling water absorbs heat from the surroundings
Show answer & explanation

Answer: C) The kinetic energy of falling water is converted into heat.

Q18. Even when the temperature reaches 46°C in summer, the camel feels relief from the heat by-

  1. ASitting in the shade of desert plants
  2. BRaising your body temperature to 42°C
  3. Cstoring water in your body
  4. Dnone of the above
Show answer & explanation

Answer: B) Raising your body temperature to 42°C

Q19. Increasing the pressure on ice increases its melting point (mp)

  1. Awill decrease
  2. Bwill increase
  3. Cwill remain unchanged
  4. Dwill become zero
Show answer & explanation

Answer: A) will decrease

Q20. Gas thermometers are more sensitive than liquid thermometers because gases-

  1. Ahas a higher specific heat
  2. Bhas a higher coefficient of expansion
  3. Care light
  4. Dhas low specific heat.
Show answer & explanation

Answer: B) has a higher coefficient of expansion

Q21. On which principle is the Thermo Couple Thermometer based?

  1. AOn the Seebeck effect
  2. BOn Joule's effect
  3. COn the Peltier effect
  4. Dnone of these
Show answer & explanation

Answer: A) On the Seebeck effect

Q22. Very high temperatures are measured by-

  1. Aplatinum resistance thermometer
  2. Bfrom a thermocouple thermometer
  3. Cfrom a total radiation pyrometer
  4. Dnitrogen gas thermometer
Show answer & explanation

Answer: C) from a total radiation pyrometer

Q23. On which principle is the Total Radiation Pyrometer based?

  1. AOn the Seebeck effect
  2. BOn the Peltier effect
  3. COn Stefan's law
  4. DOn Joule's effect
Show answer & explanation

Answer: C) On Stefan's law

Q24. Which thermometer measures the temperature of distant objects like the Sun etc.?

  1. Aby thermocouple thermometer
  2. BBy platinum resistance thermometer
  3. Cby total radiation pyrometry
  4. Dnone of these
Show answer & explanation

Answer: C) by total radiation pyrometry

Q25. In cold countries, alcohol is preferred as a thermometer liquid instead of mercury because-

  1. AAlcohols have lower melting points
  2. BAlcohol is a better conductor of heat
  3. CAlcohol is cheaper than mercury
  4. DWorld production of alcohol exceeds that of mercury.
Show answer & explanation

Answer: A) Alcohols have lower melting points

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