Heat Transfer

Q.

Name the best conductor of heat.

Q.

Explain how trapped air helps in insulation. write examples where air has applications as an insulator.

Q.

Which of the following rods will expand more, on being heated to the same rise in temperature; the initial length of each being same.

1. iron rod

2. Copper rod

3. Glass rod

4. Aluminium rod

Q.

Why does a piece of ice when touched with hand, appear cool ? Explain.

Q.

Transfer of heat from a hot object to a cold one without any medium in between them is called_____________

Q. Wooden planks are placed between railway tracks.

Q. why temperature remains onstant during inter convertion of state

Q.

Medium is necessary for the transfer of heat by radiation.

1. True
2. False

Q.

Steam of 100°C causes more severe burns than boiling water, because :

1. Kinetic energy of steam is lesser than water

2. Steam has latent heat of vaporization

3. Steam has water vapour in it

4. All the above

Q.

Explain the process by which conduction of heat occurs.

Q.

The process by which heat is transferred from one place to another without heating the intervening medium is known as ____.

Q.

Name the process of transfer of heat in mercury.

1. Convection

2. Conduction

3. Radiation

4. Expansion

Q.

Which among the following is the bad conductor of heat?

1. Iron

2. Water

3. Aluminium

4. Mercury

Q.

The transfer of heat without the help of a medium.

Q.

Which of the two contains more heat energy : $1\mathrm{kg}$ of water at $100°\mathrm{C}$ or $1\mathrm{kg}$ of steam at $100°\mathrm{C}$ ?

Q.

A medium is required for the transfer of heat by the process of :

1. radiation and conduction

2. convection and radiation

3. conduction and convection

4. conduction only

Q.

What does enthalpy mean in thermodynamics?

Q.

_____gas is responsible for combustion.

Q.

Why is a perfect heat engine impossible?

Q.

Heat is transferred by three different processes. Which of the following does not belong to the list?

1. Conduction

2. Convection

3. Radiation

4. Induction

Q.

Does work equal heat?

Q.

A good conductor of heat is :

1. asbestos

2. wood

3. air

4. mercury

Q.

1. Defne conduction?
2. Ice is kept in a double walled container why?
3. Differentiate convection and radiation

Q.

You can use a mercury thermometer to accurately infer whether mercury expands linearly with temperature

1. True
2. False

Q.

All hot objects radiate heat.

1. True
2. False

Q.

The boiling point of a gas is $-80°\mathrm{C}$. This temperature is equivalent to

1. $-193\mathrm{K}$

2. $193\mathrm{K}$

3. $353\mathrm{K}$

4. $-353\mathrm{K}$

Q.

In summer, if a wooden chair and an iron chair both kept in the sun are touched, iron chair feels warmer.

1. Iron chair

2. Wooden chair

Q.

If same amount of heat is supplied to same masses of two substances X and Y of specific heat capacities C₁ and C₂ respectively. It is given that $C_1<C_2$. So, which will show a higher rise in temperature?

Q. Heat rays reach the earth from the sun through

1. Conducion
2. Convection
3. Radiation
4. Evaporation

Q.

Which one of these things can a thermal insulator can not do?

1. Make hot things cold

2. Keep cold things cold

3. Keep warm things warm

4. None of these