Heat: MCQ Test (25 questions)

Question 1 of 25

The radiant energy emitted per second from a unit surface area of a black body is directly proportional to the fourth part of its absolute temperature. This law is:

ANewton's law of cooling
BKirchhoff's law
CStefan's law
Dlaw of thermodynamics

Question 2 of 25

If the boiling point of water in Delhi is 100°C, what will be the temperature of water in Mussoorie?

A100°C
Bless than 100°C
CMore than 100°C
DAll is false

Question 3 of 25

The function of the thermostat in a refrigerator is-

ALowering the temperature
Bincrease freezing temperature
Cmaintaining a consistent temperature
DDecreasing the melting point

Question 4 of 25

Which of the following changes occurs when salt is added to water?

Aboiling point increases and freezing point decreases
Bthe boiling point decreases and the freezing point increases
CBoth boiling point and freezing point decrease
DBoth boiling point and freezing point increase.

Question 5 of 25

Humans feel discomfort due to humidity. Which of the following is a suitable reason for this?

Aexcessive sweating
BReduced sweating
CSweat not evaporating due to humidity
Dnone of the above

Question 6 of 25

On which principle is the Thermo Couple Thermometer based?

AOn the Seebeck effect
BOn Joule's effect
COn the Peltier effect
Dnone of these

Question 7 of 25

Which part of the solar radiation heats the solar cooker?

Aultraviolet rays
Binfrared rays
Ccosmic ray
Doptical beam

Question 8 of 25

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

A4186 joules/kcal
B4.186x107 erg/calorie
C4.186 joules/calorie
DAll of the above

Question 9 of 25

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

A318K
B45K
C62.8K
D335.8K

Question 10 of 25

What is the transfer of heat through molecular structure called?

Aconduction
Bconvection
Cradiation
Dscattering

Question 11 of 25

The melting point of alloys is higher than that of their constituent metals.

AThe following are
Bare high
Care equal to
DNone of these

Question 12 of 25

The latent heat of vapor is-

A536 Cal/g
B336 Cal/g
C542 Cal/g
D340 Cal/g

Question 13 of 25

If you touch an iron block and a wooden block in the morning during cold days, the iron block feels colder because-

AThe temperature of an iron block is lower than that of a wooden block
BIron is a better conductor of heat than wood
CIron is a poor conductor of heat compared to wood.
DIron block is heavier than wood

Question 14 of 25

The two specific heats of gases are related by-

ACP – CV = R/J
BCP + CV = RJ
CCP – CV = RJ
DCP/CV = R

Question 15 of 25

The temperature of the sun is measured

Aby platinum thermometer
Bby gas thermometer
Cby pyrometer thermometer
Dby vapor pressure thermometer

Question 16 of 25

The inventor of Thermos Flask is-

ADivar
BStephen
CKirchhoff
DNewton

Question 17 of 25

The temperature at which a solid substance changes into a liquid after receiving heat is called-

ABoiling point
BMelting point
CEvaporation
DNone of these

Question 18 of 25

Stefan's law of radiation is-

AE∝1/T4
BE∝T2
CE∝T4
DE∝1/T2

Question 19 of 25

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

AArsenic
BGaliston
CSelenium
Dbromine

Question 20 of 25

Heat transfer in liquids and gases takes place by which of the following methods?

Aconduction
Bconvection
Cradiation
Dall of which

Question 21 of 25

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

AAlcohols have lower melting points
BAlcohol is a better conductor of heat
CAlcohol is cheaper than mercury
DWorld production of alcohol exceeds that of mercury.

Question 22 of 25

Water is used to cool the radiator of an automobile because-

Awater has a high specific heat
Bthe density of water is low
CWater is cheap
DWater is available at low temperature.

Question 23 of 25

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

ASitting in the shade of desert plants
BRaising your body temperature to 42°C
Cstoring water in your body
Dnone of the above

Question 24 of 25

What is the process called when a liquid changes into its vapor before its boiling point?

Aevaporation
Bcompaction
Cfreezing
Dnone of these

Question 25 of 25

During the day, the earth heats up much faster than the sea water because-

AThe density of the Earth is greater than that of water
BDue to aquatic animals living in the sea
CThe specific heat capacity of water is very high
Dwater is made up of hydrogen and oxygen