CBSE Questions for Class 7 Physics Heat Quiz 1 - MCQExams.com

Two layers of cloth of equal thickness provide warmer covering than a single layer of cloth of double the thickness, because they :
  • behave like a thermos
  • have lesser thickness
  • allow heat from atmosphere to the body
  • enclose between them a layer of air
When a body has the same temperature as that of its surroundings :
  • It does not radiate heat
  • It radiates same quantity of heat as it receives from the surroundings
  • It radiates less quantity of heat as it receives from the surroundings
  • It radiates more quantity of heat as it receives from the surroundings.
Which of the following methods of flow of heat is (are) based on gravitational attraction?
  • Conduction
  • Convection
  • Radiation
  • All of these
In a room containing air, heat can go from one place to another by :
  • conduction
  • convection
  • radiation
  • all of these
Assertion (A): Woolen clothes keep the body warm in winter
Reason (R): Air is bad conductor of heat
  • Both A and R are true,
  • Both A and R are false
  • Both A and R are true, R is correct explanation of A
  • Both A and R are true, R is not correct explanation of A
A) Heat transfer by conduction and convection require a material medium.
B) Heat transfer by radiation doesn't require a material medium.
  • both A and B are true
  • A is true but B is false
  • B is true but A is false
  • both A and B are false
In the following, which statement is correct :
a) A hot body emits hot radiations only.
b) A cold body absorbs the radiations only.
c) A cold body emits cold radiations only.
d) All the bodies emit and absorb radiations simultaneously.
  • a
  • b
  • c
  • d
Celsius is a unit of :
  • Temperature
  • Heat
  • Specific heat
  • Latent heat
Radiation is passing through a transparent medium, then :
  • the temperature of medium increases
  • the temperature of medium decreases
  • the temperature of medium does not alter
  • the temperature of medium first increases and then becomes steady
The range of clinical thermometer is:
  • $$35^{\circ}C$$ to $$42^{\circ}C$$
  • $$35^{\circ}F$$ to $$42^{\circ}F$$
  • $$90^{\circ}F$$ to $$112^{\circ}F$$
  • $$90^{\circ}C$$ to $$112^{\circ}C$$
  • Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
  • Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
  • Assertion is correct but Reason is incorrect
  • Assertion is incorrect but Reason is correct
Heat travels much faster in insulators than in conductors.
  • True
  • False
Ventilators are provided at the top of a room:
  • To bring oxygen for breathing.
  • So that sunlight may enter the room.
  • To maintain convectional currents to keep the air fresh in the room.
  • To provide an outlet for carbon dioxide.
As we go down into the earth, the temperature .................... ?
  • Decrease
  • Constant
  • Increases
  • Not depend
To measure high temperatures $$> 2500^oC$$, we use
  • constant volume gas thermometer
  • thermocouple
  • resistance thermometer
  • pyrometer
The degree of hotness or coldness of the body is called temperature.
  • True
  • False
Sun's heat reaches the earth by the process of:
  • Conduction
  • Convection
  • Radiation
  • Scattering
Ebonite handles are used to handle hot utensil because they are bad conductors of heat.
  • True
  • False
The kinetic energy of molecules of a gas increases with:
  • Fall in temperature
  • Rise in temperature
  • Decrease in pressure
  • All of the above
What is S.I. unit of temperature?
  • Kelvin
  • Degree Celsius
  • Fahrenheit
  • All of the above
In a solid, heat is transferred mainly by the process of
  • conduction
  • convection
  • radiation
  • conduction and convection both
Name the material used for making the handles of cooking utensils.
  • Bakelite
  • Aluminium
  • Steel
  • Plastic
Heat is transmitted from higher to lower temperature through actual mass motion of the molecules in
  • conduction
  • convection
  • radiation
  • None of these
A good insulator of heat is
  • copper
  • mercury
  • trapped air
  • iron
Name a metal among the following having highest heat conductivity .
  • Silver
  • Copper
  • Aluminium
  • Brass
Which of the following is the very poor conductor of heat ?
  • Water
  • Metals
  • Liquid other than water
  • Steam
The process of heating a pan on stove is an example of
  • Conduction.
  • Convection.
  • Radiation.
  • Insulation.
Which serves the purpose of an insulator?
  • Still air
  • Moving air
  • Both
  • None
If a liquid is heated in weightlessness, the heat is transmitted through
  • conduction
  • convection
  • radiation
  • None of these, because the liquid cannot be heated in weightlessness
Name a medium which is a good insulator of heat.
  • Still (or trapped) air
  • Oil
  • Steam
  • solid copper
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