Paper 1 and 2 heat energy etc

Question 1

What is internal energy and what is it the sum of

Answer 1

The energy stored by the particles and is caused by their individual motion and positions and is the sum of the kinetic energy of all particles and the potential energy of all the particles

Question 2

What does internal energy not include

Answer 2

Gravitational potential energy or kinetic energy caused by the motion of the whole substance

Question 3

What happens to the internal energy when a substance is heated

Answer 3

The kinetic energy increases so the internal energy increases

Question 4

What is the specific heat capacity

Answer 4

The amount of energy required to raise 1kg of material by 1 degree

Question 5

What factors affect how much energy must be gained by an object as it’s temperature increases

Answer 5

Temperature increases
Mass, more energy needed
Materials, some need more energy than others

Question 6

Specific heat energy equation

Answer 6

Energy= mass x specific heat capacity x temperature change

Question 7

What’s specific latent heat and what does it depend on

Answer 7

The energy transferred to a substance when it changes state measure in J it depends on the mass of the substance and the state it is in

Question 8

The energy calculated in specific latent heat

Answer 8

It’s the change in internal energy. Since the temp is constant during change of state, the kinetic energy stays the same but poten. ener increases as bonds are bulle daprt

Question 9

Latent heat energy equation

Answer 9

Energy= mass x specific latent heat

Question 10

What are the three processes that heat can be transferred

Answer 10

Conduction
Convection
Radiation

Question 11

What is conduction

Answer 11

Particles that are very close together transfer heat energy as they vibrate

Question 12

How do non-metals conduct

Answer 12

That atoms near the heat source gain kinetic energy and vibrate more. As they collide with neighbouring atoms, the energy is passed on

Question 13

How do metals conduct

Answer 13

The outer electrons of metal atoms are not attached to any particular atom. They are free to move between the atoms

Question 14

Why are gases poor insulators

Answer 14

The particles in a gas are too far apart for collisions to transfer energy effectively

Question 15

What is the best insulator

Answer 15

A vacuum because there are no particles to collide and pass on the energy

Question 16

Good insulating materials

Answer 16

Polystyrene
Foam
Fibre glass
Cotton wool

Question 17

Why are wool and fibre glass good insulators

Answer 17

Because they have lots of trapped air which is a poor conductor

Question 18

What are the best insulators

Answer 18

Materials with the lowest thermal conductivity

Question 19

What happens to the particles when a fluid is heated

Answer 19

They gain energy and spread out decreasing the density

Question 20

Convection can’t happen in…

Answer 20

Solids because the particles aren’t free to flow

Vacuums because there aren’t any particles to flow

Question 21

What is infrared radiation.

Answer 21

The transfer of energy by electromagnetic waves e.g. the sun heats the earth by infrared radiation as there are no particles is space to transfer the energy

Question 22

What is the best emitter of thermal radiation

Answer 22

Matt black

Question 23

What’s the worst emitter of thermal radiation

Answer 23

Silver

Question 24

Good emitters are also

Answer 24

Good absorbers

Question 25

What’s a perfect black body

Answer 25

An object that absorbs all the radiation that hits it and doesn’t transmit any radiation. A black body is the best possible emitter

Question 26

What happens to the intensity of the radiation if the temperature increases

Answer 26

It increases at every wavelength and the peak moves to a shorter wavelength (higher frequency)

Question 27

What does the temperature of the earth depend on

Answer 27

The rate that light and infrared radiation from the sun are absorbed by the atmosphere or surface and are reflected back into space
the rate at which the earth emits radiation from its surface and atmosphere

Question 28

Examples of convection

Answer 28

In a fridge, the freezer at the top cools air at top and cools food on the way down. The air is warmer at the bottom, this warm air rises creating a convection current

Question 29

Convection current in house

Answer 29

Convection causes heat to be lost through the roof. Loft insulation helps to reduce this

Question 30

What’s a thermograph

Answer 30

These images are taken using infrared radiation. the different colors show which parts are emitting more infrared

Question 31

How does heat energy flow

Answer 31

Flows from a hot object to a cooler one

Question 32

What happens to a filament lamp as it warms up?

Answer 32

It glows a dull red as it is emitting the red part of the visible spectrum as well as infrared. Then turns orange-red to white as it gets hotter

Question 33

Why does the filament lamp change colour as it heats up

Answer 33

Because it emits more radiation at shorter wavelengths as it gets hotter