P2 Heat energy transfers

Question 1

Describe conduction
(2 marks)

Answer 1

-Occurs only in solids
-passes on kinetic energy
-particles collide

Question 2

Metals usually have a high what?

Answer 2

thermal conductivity

Question 3

Plastics are insulators and have what characteristic?

Answer 3

low thermal conductivity

Question 4

What must a material have in order to be a good insulator?
(2 marks)

Answer 4

-Low thermal conductivity
-air pockets

Question 5

how does trapped air insulate?

Answer 5

Limits convection as particles cannot move around as much and take thermal energy with them.

Question 6

What is convection?
(2 marks)

Answer 6

-Water and gasses
-particles take energy and diffuse away, while being replaced

Question 7

What is radiation?
(2 marks)

Answer 7

-energy that travels in a wave
-doesn’t need particles, can travel through vacuums

Question 8

Which colour would absorb more radioactive waves?
black or white

Answer 8

black

Question 9

Which colour would emit more radioactive waves?
black or white

Answer 9

black

Question 10

Why does white reflect more radioactive waves than black?

Answer 10

Lighter so it blocks more wavelengths.

Question 11

Do shiny or matte surfaces reflect radiation?

Answer 11

shiny

Question 12

Why do matte surfaces absorb more radiation compared to shiny surfaces?

Answer 12

matte surfaces have a rough texture on microscopic level making reflecting waves more difficult

Question 13

what is the symbol equation for specific heat capacity?

Answer 13

E=m c θ

Question 14

what is the word equation for specific heat capacity

Answer 14

energy= mass x specific heat capacity x theta

Question 15

What is the unit for c

Answer 15

Specific heat capacity:
joules per kg/degrees Celsius.

Question 16

Where in a house is most of the heat lost? And why?

Answer 16

The loft because heat rises

Question 17

What is the measurements for the equation:
E=m c θ

Answer 17

E= J
m= kg
c= j kg/degrees Celsius
θ=Temperature change degrees Celsius

Question 18

Structure the triangle for the equation: E=m c θ

Answer 18

E
m c θ

Question 19

DEFINE specific heat capacity word for word.

Answer 19

The specific heat capacity of a substance is the energy needed to raise the temperature of 1kg by 1 degree.

Question 20

Name 3 ways of limiting heat loss in buildings

Answer 20

loft insulation
double glazing windows
cavity walls
rugs and carpets