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Heat

179 MCQ questions with answers and explanations · page 7 of 8

Q151. Mercury is generally used in thermometers because it has-

  1. Ahave high liquidity
  2. Bhas a high density
  3. Chas high conductivity
  4. DHas a high specific heat (SSC)
Show answer & explanation

Answer: C) has high conductivity

Q152. Boiling point (BP) of liquid due to impurities –

  1. Aincreases
  2. Bhappens to
  3. Cremains the same
  4. DThere is no connection
Show answer & explanation

Answer: A) increases

Q153. The temperature at a place on a sunny day is 113 on the Fahrenheit scale. What is the Kelvin scale reading of this temperature?

  1. A318K
  2. B45K
  3. C62.8K
  4. D335.8K
Show answer & explanation

Answer: A) 318K

Q154. Food is cooked in less time in a pressure cooker because-

  1. AThe temperature of boiling water decreases due to high pressure.
  2. BIt is closed from all sides and hence does not have any effect on air.
  3. CDue to high pressure the temperature of boiling water increases.
  4. DEvaporation of the water used is very low.
Show answer & explanation

Answer: C) Due to high pressure the temperature of boiling water increases.

Q155. On what does the specific heat of an object depend?

  1. Aon the mass of the body
  2. Bon the heat provided to the body
  3. Con the mass of the body
  4. Dat the body temperature
Show answer & explanation

Answer: A) on the mass of the body

Q156. It is comfortable to wear white clothes in summer because-

  1. AThey reflect all the heat falling on them.
  2. BThey develop all the heat transferred from the body
  3. CThey absorb sweat
  4. DIt provides coolness to the eyes
Show answer & explanation

Answer: A) They reflect all the heat falling on them.

Q157. Why is the outer bottom of cooking utensils left black?

  1. AIt is difficult to clean it daily.
  2. BBlack surface is a good conductor of heat
  3. CBlack surface is a bad conductor of heat
  4. DBlack surfaces are good heat absorbers
Show answer & explanation

Answer: D) Black surfaces are good heat absorbers

Q158. What does a white and smooth surface look like?

  1. APoor absorber and poor reflector of heat
  2. BGood absorber and good reflector of heat
  3. Cpoor absorber and good reflector of heat
  4. DGood absorber and poor reflector of heat
Show answer & explanation

Answer: C) poor absorber and good reflector of heat

Q159. The rate of vaporization of a liquid does not depend on what?

  1. Aat temperature
  2. Bon humidity
  3. Con its mass
  4. Don its surface area raised in the atmosphere
Show answer & explanation

Answer: D) on its surface area raised in the atmosphere

Q160. thermometer suitable for measuring 2000°C is-

  1. AVapor Pressure Thermometer
  2. Bmercury thermometer
  3. CFull radiation pyrometer
  4. Dgas thermometer
Show answer & explanation

Answer: C) Full radiation pyrometer

Q161. Which of the following is used as a substitute for mercury in thermometers?

  1. AArsenic
  2. BGaliston
  3. CSelenium
  4. Dbromine
Show answer & explanation

Answer: B) Galiston

Q162. Why can two thin shirts keep us warmer in winter than one thick shirt?

  1. ATwo thin shirts become thicker, hence preventing the transfer of heat
  2. BThe layer of air between the two shirts acts as a conductor.
  3. CThe layer of air between the two shirts acts as a medium of insulation.
  4. DThere is no radiation of heat
Show answer & explanation

Answer: C) The layer of air between the two shirts acts as a medium of insulation.

Q163. Which of the following has greater heat capacity?

  1. Apiece of iron
  2. BWater
  3. Cpiece of gold
  4. DWenjin
Show answer & explanation

Answer: B) Water

Q164. If there is a sudden increase in the temperature of a place, then the relative humidity-

  1. Aincreases
  2. Bdecreases
  3. Cremains stable
  4. DIt keeps increasing and decreasing.
Show answer & explanation

Answer: B) decreases

Q165. Which temperature measured in Celsius is equal to 300 K?

  1. A30°C
  2. B27°C
  3. C300°C
  4. DNone of these
Show answer & explanation

Answer: B) 27°C

Q166. The heat required to convert a substance from liquid to gas without any change in temperature is called its latent heat?

  1. AEvaporation
  2. BUplift
  3. Ccompaction
  4. Devaporation
Show answer & explanation

Answer: A) Evaporation

Q167. Whose radiation can a black body absorb?

  1. Aonly low wavelengths
  2. Bintermediate wavelengths only
  3. Chigh wavelength only
  4. Dall wavelengths
Show answer & explanation

Answer: C) high wavelength only

Q168. During winter, when the weather is of what type, we feel more cold?

  1. Aclear weather
  2. Bcloudy weather
  3. Chumid weather
  4. Ddry weather
Show answer & explanation

Answer: A) clear weather

Q169. To convert the temperature taken on Kelvin scale to Celsius scale, the given temperature will be in ........

  1. AAdding 273
  2. BDividing by 273
  3. CMultiplying by 273
  4. Dsubtract 273
Show answer & explanation

Answer: D) subtract 273

Q170. Why is ice packed in sawdust?

  1. ASawdust doesn't stick to ice
  2. BSawdust does not melt easily
  3. CSawdust is a bad conductor of heat
  4. DSawdust is a good conductor of heat
Show answer & explanation

Answer: C) Sawdust is a bad conductor of heat

Q171. Due to which of the following processes the water in an earthen pot remains cool?

  1. Aliquefaction
  2. Bevaporation
  3. CUplift
  4. DNone of these
Show answer & explanation

Answer: B) evaporation

Q172. On what does the rate of cooling depend?

  1. Athe difference in temperature between the body and its surroundings
  2. BRadiating surface area
  3. CNature of the radiating surface
  4. DAll of the above
Show answer & explanation

Answer: A) the difference in temperature between the body and its surroundings

Q173. The two specific heats of gases are related by-

  1. ACP – CV = R/J
  2. BCP + CV = RJ
  3. CCP – CV = RJ
  4. DCP/CV = R
Show answer & explanation

Answer: A) CP – CV = R/J

Q174. Sweating cools the body because-

  1. AThe presence of water on the skin provides coolness.
  2. Blatent heat is required for vaporization
  3. Cwater has a high specific heat
  4. Dwater is a poor conductor of heat
Show answer & explanation

Answer: B) latent heat is required for vaporization

Q175. If the temperature of a system is x in Kelvin andoIf C contains y then the relation between them is-

  1. Ax=273-y
  2. Bx=273+y
  3. Cx=173+y
  4. Dx=173-y
Show answer & explanation

Answer: B) x=273+y

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