Notes

Question 1

Dark Matt surfaces are…

Answer 1

…good at emitting and absorbing radiation

Question 2

Shiny, light surfaces are…

Answer 2

Poor at absorbing and emitting. Good reflectors

Question 3

What is conduction

Answer 3

Conduction is the transfer of energy in the form of heat

Question 4

What is convection?

Answer 4

Convection is when heat energy is transferred from hot places to cooler places.Convection occurs when particles with a lot of heat energy in a liquid or gas move and take the place of particles with less heat energy.

Question 5

Why do rescue teams you thermal blankets to keep accident survivors warm

Answer 5

They use thermal blankets because a thermal has a light, shiny outer surface. This mean it emits my ch less radiation than a dark, Matt surface

Question 6

What does the vacuum between the glass walls of a thermos reduce?

Answer 6

The vacuum reduces conduction and convection

Question 7

What do the silvered surfaces of the glass walls reduce?

Answer 7

The silver surfaces reduce radiation

Question 8

If the mass of the metal case is 100kg, the starting temperature is 20degrees, the ending temperature is 70 degrees and the the specific heat capacity is 510J/Kg. calculate the energy required to raise the temperature of the metal case to 70 degrees

Answer 8

E Energy required = mass × specific heat capacity × temperature change

2555000000

Question 9

Why does skin feel cold after rubbing alcohol is applied to it?

Answer 9

When the alcohol evaporates, it absorbs heat so it feels cold from both the skin underneath it and from the air around it.

Question 10

Why does a liquid cool down when it evaporates?

Answer 10

When the liquid evaporates the bonds between the particles break and the particles with the highest kinetic energy escape from the liquid. The liquid left behind has less energy than it did before evaporation occurred.therefore the temperature of the liquid is lower

Question 11

What does the statement “volume is inversely proportional to pressure” mean?

Answer 11

It means that if the pressure is doubled, the volume is halved

Question 12

Why does a balloon expand when air is blown into it?

Answer 12

A balloon expands because the pressure of the air molecules is greater on the inside of the balloon than the outside

Question 13

What is the order of the electromagnetic spectrum

Answer 13

Gamma rays, X-Rays, Ultraviolet, (visible) Light, Infared, Microwaves and Radio waves

Question 14

Which wave has the shortest wave length?

Answer 14

Gamma rays have the shortest wavelength

Question 15

Which waves have the longest wavelength?

Answer 15

Radio waves have the longest wavelength

Question 16

All electromagnetic waves travel at the same…

Answer 16

… Speed in a vacuum

Question 17

Why does conduction take place in solids especially metals?

Answer 17

because in metals the particles are closely packed together meaning that vibrations can easily pass through them

Question 18

What thing do metals have that allow them to move and carry around heat energy?

Answer 18

Metals have free electrons

Question 19

Insulators………..by conduction

Answer 19

Insulators REDUCE HEAT MOVEMENT by conduction

Question 20

What does the stopper in the opening of the flask reduce?

Answer 20

The stopper reduces evaporation and convection

Question 21

Give one environmental advantage to turning off electrical appliances when they are not being used

Answer 21

It reduces the amount of fossil fuels used

Question 22

They pumped storage hydro electric system can also be used as a way of storing energy for future use. Explain how

Answer 22

The water is pumped up to a higher reservoir so it can be accessed

Question 23

Explain what happens to particles when water changes from a gas to a liquid

Answer 23

When water changes from a gas to a liquid, the particles loose heat energy when cooled and the kinetic energy decreases. The particles also get closer to each other

Question 24

Explain the process of conduction through metals

Answer 24

The free electrons gain kinetic energy and particles vibrate this energy is transferred to the ions that help transfer heat energy through the metal the particles get faster and there is more collisions occurring

Question 25

Give some properties of the same for both radio waves and microwaves

Answer 25

They both can get through the Earth’s atmosphere, they can both travel through a vacuum, they can both be absorbed and they travel at the same speed through the air