# Physics

HideShow resource information
• Created by: plu10710
• Created on: 08-04-14 11:18
What substance can convection happen in?
Liquids and gases
1 of 25
What type of radiation do all hot objects emit?
2 of 25
What are the best and worst absorbers of thermal radiation?
The best are black, dull surfaces and the worst are light, shiny surfaces
3 of 25
How does heat pass through a single pane of window glass?
By conduction and convection
4 of 25
Insulating a home costs £1800 and saves £50 a year. What is the payback time?
36 years
5 of 25
Why does 'wasted energy' become less useful?
Because it becomes increasingly spread out
6 of 25
In a certain device, 25% of the energy is usefully transferred. What is the energy efficiency of this device?
25%
7 of 25
A coal-fired power station is 40% efficient. What does this mean?
40% of the chemical energy stored in the coal is transferred to electrical energy
8 of 25
Using Source C, how much energy is transferred by a 500 W electric drill in 30 seconds?
15,000 J
9 of 25
A 250 W computer is switched on for 4 hours. How many Units of electricity does it use?
1 Unit
10 of 25
A 2 kW electric fire is switched on for 30 minutes. How many Units of electricity does it use?
1 Unit
11 of 25
If one Unit of electricity costs 10p, how much will 30 units cost?
£3
12 of 25
What is the distance from the crest of one wave to the crest of the next wave called?
The wavelength
13 of 25
What are the units of frequency?
Hz (Hertz)
14 of 25
What is the direction of a light wave to the direction of enerfy transfer?
Perpendicular to the direction of energy transfer
15 of 25
What is shown in Source D?
Reflection
16 of 25
What is shown in Source E?
Refraction
17 of 25
What is shown in Source F?
Diffraction
18 of 25
Using Source F, why do you need a small gap?
Because light has a small wavelength
19 of 25
How do signals travel through optical fibres?
20 of 25
Microwaves are used because they are not refracted by the atmosphere and because they can travel through the ionosphere. Radio waves are not used because they reflect off the ionosphere
21 of 25
What piece of evidence supports the Big Bang theory?
The more distant galaxies are moving the quickest
22 of 25
Why is the light from galaxies red-shifted?
They are moving away from us
23 of 25
According to the Doppler effect, what happens to sound waves emitted at a constant pitch from a car moving towards you?
Their frequency increases, so their pitch increases
24 of 25
What is the CMBR?
25 of 25

## Other cards in this set

### Card 2

#### Front

What type of radiation do all hot objects emit?

### Card 3

#### Front

What are the best and worst absorbers of thermal radiation?

### Card 4

#### Front

How does heat pass through a single pane of window glass?

### Card 5

#### Front

Insulating a home costs £1800 and saves £50 a year. What is the payback time?