Heat and Heat transfer

Question 1

Thermometric property of mercury thermometer

Answer 1

Volume increases and therefore the length of the column of liquid in it expands

Question 2

Thermometric property of a thermocouple

Answer 2

when two metals are joined together at different temperature a small EMF appears in it

Question 3

Kelvin to degree =

Answer 3

(no. of Kelvins - 273.15)˚C

Question 4

Degree to Kelvin =

Answer 4

(no. of degrees + 273.15)K

Question 5

Heat capacity

Answer 5

heat energy needed to change it’s temperature by 1K(1˚C)

Question 6

Specific heat capacity =

Answer 6

heat energy needed to change the temperature of 1kg of that substance by 1K

Question 7

Unit of specific heat capacity

Answer 7

J/kg K

Question 8

Specific latent heat

Answer 8

heat energy needed to change the state of 1kg of that substance without a change in temperature

Question 9

U-value

Answer 9

amount of heat energy conducted per 1 second through 1m(squared) of that structure when a temperature difference of 1˚C is maintained between its ends

Question 10

Radiation

Answer 10

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

Question 11

Solar constant

Answer 11

average amount of the sun’s energy falling per second perpendicularly on 1 metre squared of the earth’s atmosphere. 1kW

Question 12

Convection

Answer 12

transfer heat through a fluid by means of circulating currents caused by the heat

Question 13

Conduction

Answer 13

movement of heat energy through a substance by the passing ono molecular vibrations from molecule to molecule. No overall motion of the substance

Question 14

Temperature

Answer 14

Average kinetic energy in a particle

Question 15

Heat pump

Answer 15

A pipe containing a fluid, this fluid then passes through an expansion valve and therefore has a low boiling point

Changes into a gas in your desired area such as a fridge and as it changes absorbs all the heat(energy) from its area and therefore cools the fridge

Then passes through a compressor and exits the fridge, changes back into a liquid due to high pressure and releases all the heat energy into to the atmosphere

Question 16

2 properties of a liquid in a heat pump

Answer 16

High specific capacity of latent heat of fusion of vaporisation

low boiling point