Heat: MCQ Test (50 questions)

Question 1 of 50

The rate of evaporation for a given liquid depends on-

Aat the temperature of the liquid
Bat air temperature
Cthe area of the open surface of the liquid
Don all the above factors

Question 2 of 50

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

Aconduction
Bconvection
Cradiation
Dall of which

Question 3 of 50

Water pipelines in the mountains burst during extreme winter. This is because:

AThe pipe shrinks due to cold.
BWater in pipes shrinks when it freezes
CWater in pipes expands when it freezes
DPipes expand as they cool

Question 4 of 50

Whose radiation can a black body absorb?

Aonly low wavelengths
Bintermediate wavelengths only
Chigh wavelength only
Dall wavelengths

Question 5 of 50

Gas thermometers are more sensitive than liquid thermometers because gases-

Ahas a higher specific heat
Bhas a higher coefficient of expansion
Care light
Dhas low specific heat.

Question 6 of 50

Water is used in hot water bags because-

AIt is easily available.
BIt is cheap and not harmful.
CIts specific heat is high
DIt is easy to heat water

Question 7 of 50

Which part of the solar radiation heats the solar cooker?

Aultraviolet rays
Binfrared rays
Ccosmic ray
Doptical beam

Question 8 of 50

The rate of evaporation does not depend on-

Aat the temperature of the liquid
Bon the surface area of the liquid
Cover the entire volume of the liquid
Dat air pressure

Question 9 of 50

The unit of temperature in the SI system is-

AKelvin
BDegree Celsius
Cdegree centigrade
Ddegrees Fahrenheit

Question 10 of 50

Which of the following has the highest value of specific heat?

Aglass
BCopper
Clead
DWater

Question 11 of 50

Hot water takes 10 minutes to cool from 90°C to 80°C, then it will take time to cool from 80°C to 70°C-

A10 minutes
BLess than 10 minutes
Cmore than 10 minutes
DNot sure

Question 12 of 50

It is comfortable to wear white clothes in summer because-

AThey reflect all the heat falling on them.
BThey develop all the heat transferred from the body
CThey absorb sweat
DIt provides coolness to the eyes

Question 13 of 50

Why do bicycle tubes burst mostly in summer?

AThe tube bursts due to heat.
BRubber becomes very weak due to heat.
CHeat causes the rubber to harden and not expand to accommodate air.
Dnone of the above

Question 14 of 50

The boiling point of a liquid increases with increase in pressure.

Awill decrease
Bwill increase
Cwill remain unchanged
DSometimes it will decrease and sometimes it will increase

Question 15 of 50

How many degrees centigrade is 14 degrees Fahrenheit?

A-20
B20
C-10
D10

Question 16 of 50

What is the transfer of heat through molecular structure called?

Aconduction
Bconvection
Cradiation
Dscattering

Question 17 of 50

Ice skating demonstrates that increasing the pressure lowers the melting point of ice.

Aincreases
Bremains unchanged
Chappens to
Dfirst decreases then increases

Question 18 of 50

Running a fan in hot weather gives relief because-

AThe fan gives cool air.
BOur sweat evaporates faster.
COur bodies radiate more heat
DThe conductivity of air increases.

Question 19 of 50

The process of preparing camphor vapour from solid camphor is called-

Aevaporation
Bfreezing
Cmelt
DUplift

Question 20 of 50

Dew does not form on a windy night because-

AThe rate of evaporation is faster
BThere is less moisture in the air
CThe temperature remains high
DThe sky is not clear

Question 21 of 50

The reason why the snow covering the mountains does not melt all at once due to the heat of the sun is-

AIt becomes very hard
BIt reflects most of the heat received from the sun.
CIt has a low specific heat capacity
DIt has high latent heat of fusion

Question 22 of 50

Which of the following is the best conductor of heat?

AWater
BMercury
CWood
Dleather

Question 23 of 50

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 24 of 50

Boiling Point of Water-

Ais always 100°C
Bdepends on the material of the container
Cdepends on the relative humidity
Ddepends on the pressure above the open surface of water

Question 25 of 50

Food gets cooked in less time in a pressure cooker because-

Athe boiling point of water increases
Bthe boiling point of water decreases
CFood takes in less heat
Dneither of the above

Question 26 of 50

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

Akinetic energy has increased
BThe potential energy has increased.
Cmechanical energy has increased
DThermal energy has increased.

Question 27 of 50

The change of state of matter from solid to liquid is called-

Amelting
BEvaporation
Cboiling
DNone of these

Question 28 of 50

The thermal conductivity of silver is higher than that of copper.

Aare less
Bis more
Cis equal to
Dnone of these

Question 29 of 50

The heat required to raise the temperature of a unit mass of a substance by one degree Celsius is-

Aspecific heat
Bheat capacity
Cwater equivalent
Dlatent heat

Question 30 of 50

The temperature of an object on the Fahrenheit scale is 212°F. Its temperature on the Celsius scale would be

A- 32°C
B40°C
C100°C
D112°C

Question 31 of 50

Black skinned people from Africa compared to white skinned people from Britain-

Afeel more heat
Bfeel less heat
Cfeel the same heat
DDo not feel the heat

Question 32 of 50

The temperature at which ice, water and vapour remain in equilibrium is called—

AFreezing point
BBoiling point
Ccritical temperature
Dtriple point

Question 33 of 50

The normal temperature of the human body in Kelvin is-

A280
B290
C300
D- 273°C

Question 34 of 50

Why are white clothes cooler than black clothes?

Aabsorb all light that reaches them
BThey reflect whatever light reaches them.
Cdoes not allow light to penetrate
DCompletely cools the sunlight

Question 35 of 50

Water kept in an earthen pot cools down during summer days due to the following phenomenon-

Adiffusion
Btranspiration
COsmosis
Devaporation

Question 36 of 50

If a metal is used to make cooking utensils, then the heat conductivity-

Ashould be less
BThere should be more
CElectrical conductivity should be low
DThe density should be high

Question 37 of 50

Cryogenic engines are used in-

AIn submarine propulsion
Bin frost-free refrigerators
Cin rocket technology
Din research on superconductivity

Question 38 of 50

On which principle is the Total Radiation Pyrometer based?

AOn the Seebeck effect
BOn the Peltier effect
COn Stefan's law
DOn Joule's effect

Question 39 of 50

The first law of thermodynamics conserves

AImpulse
Benergy
Cboth momentum and energy
Dnone of these

Question 40 of 50

When water is filled in a bottle and allowed to freeze, the bottle breaks because-

Awater expands when it freezes
BThe bottle contracts at freezing point.
CThe temperature outside the bottle is higher than inside.
Dwater expands when heated

Question 41 of 50

Steam burns are more painful (serious) than boiling water burns.

ASteam has latent heat,
BSteam is a type of gas and it immerses the body quickly.
CSteam easily enters the body through the pores present in the body.
DSteam has a very high temperature

Question 42 of 50

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

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

Question 43 of 50

Stefan's law of radiation is-

AE∝1/T4
BE∝T2
CE∝T4
DE∝1/T2

Question 44 of 50

Which of the following has greater heat capacity?

Apiece of iron
BWater
Cpiece of gold
DWenjin

Question 45 of 50

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

AEvaporation
BUplift
Ccompaction
Devaporation

Question 46 of 50

By which method are the walls of a thermos flask coated to minimize heat transfer?

Aconduction
Bconvection
Cradiation
Dall of which

Question 47 of 50

The normal body temperature of a human being is-

A98°F
B98°C
C68°F
D66°F

Question 48 of 50

Sublimate substance is-

AKapoor
BNaphthalene
Cammonium chloride
DAll of the above

Question 49 of 50

Which of the following liquids is a very good conductor of heat?

AMercury
BWater
CEther
Dbenzene

Question 50 of 50

Sweating cools the body because-

AThe presence of water on the skin provides coolness.
Blatent heat is required for vaporization
Cwater has a high specific heat
Dwater is a poor conductor of heat