Quantity of Heat and Heat Transfer

Question 1

Heat capacity

Answer 1

The heat capacity of an object is the heat energy needed to change its temperature by 1 K

Question 2

Specific heat capacity

Answer 2

The specific heat capacity (c) of a substance is the heat energy needed to change the temperature of 1 kg of that substance by one kelvin

Question 3

Unit of specific heat capacity

Answer 3

The unit of specific heat capacity is the joule per kilogram per kelvin ( J / kg / K )

Question 4

Latent heat

Answer 4

The latent heat (L) of a substance is the heat energy needed to change its state without a change in temperature

Question 5

Specific latent heat

Answer 5

The specific latent heat (l) of a substance is the amount of heat energy needed to change the state of 1 kg of that substance without a change in temperature

Question 6

Specific latent heat of fusion

Answer 6

The specific latent heat of fusion of a substance is the amount of heat energy needed to change 1 kg of that substance from a solid to a liquid without a change in temperature

Question 7

Specific latent heat of vaporisation

Answer 7

The specific latent heat of vaporisation of a substance is the amount of heat energy needed to change 1 kg of that substance from a liquid to a gas without a change in temperature

Question 8

Unit of specific latent heat

Answer 8

The unit of specific latent heat of vaporisation and of fusion is the joule per kilogram ( J / kg )

Question 9

Conduction

Answer 9

Conduction is the movement of heat energy through a substance by the passing on of molecular vibration from molecule to molecule. There is no overall movement of the substance

Question 10

U-Value

Answer 10

The u-value of a structure is the amount of heat energy conducted per second through 1 m*2 of that structure when a temperature difference of 1 degree Celsius is maintained between its ends

Question 11

Radiation

Answer 11

Radiation is the transfer of heat energy from one place to another in the form of electromagnetic waves

Question 12

Solar constant (solar irradiance)

Answer 12

The average amount of the Sun’s energy falling per second perpendicularly on 1 metre squared of the Earth’s atmosphere is the solar constant. Its value is about 1.35 kW / m*2

Question 13

Convection

Answer 13

Convection is the transfer of heat through a fluid by means of circulation currents of fluid caused by the heat