Domestic Uses and Safety (2)

Question 1

What happens to the energy wasted by the light bulb?

Answer 1

It is transferred to the surroundings by heating

Question 2

Suggest why the homeowner is likely to choose LED bulbs

Answer 2

Uses less power and lasts longer. 1 LED costs £16 and 40 filament bulbs cost £80

Question 3

Suggest why it is important to confirm this information independently

Answer 3

To avoid bias

Question 4

State one factor, other than efficiency, that is important when considering the choice of a bulb for lightning in the home

Answer 4

Availability of bulbs

Question 5

What colour is the insulation around the wire to the live pan inside the plug?

Answer 5

Brown

Question 6

Why does the hairdryer not need an earth wire?

Answer 6

Outside case is an insulator

Question 7

Which switch or switches have to be ON to make:
(1) only the fan work
(2) heater 2 work

Answer 7

(1) S
(2) S and S

Question 8

The heaters can only be switched on when the fan is also switched on.
Explain why

Answer 8

S must be on for the heater to work so S switches on

Question 9

Evaluate in terms of cost and energy efficiency, the use of the two types of light bulb

Answer 9

• halogen are cheaper to buy
• 6 halogen lamps cost the same as one LED
• LEDs last longer
• LEDs work using a smaller current
• LED wastes less energy
• LEDs are more efficient

Question 10

A fuse is connected in the _______ wire
RCCBs are sometimes preferred to fuses because they ___________
The two wires are the _______ and _________

Answer 10

• live
• react faster
• live and neutral

Question 11

State two extra components that must have been included in the circuit in the figure above to allow the data in the above table to be collected

Answer 11

Ammeter to measure current and variable resistor to vary current

Question 12

Suggest two changes that would allow lower values of current to be used in this investigation

Answer 12

• use smaller masses
• move mass closer to pivot

Question 13

The system could work well because the road surface is black.
Suggest why

Answer 13

Black is a good absorber of infrared radiation

Question 14

What is meant by specific latent heat of fusion?

Answer 14

Amount of energy required to change the state of a substance from solid to liquid with no change in temperature

Question 15

The student added salt to crushed ice and measured the temperature at which the ice melted.
State one variable that the student should have controlled

Answer 15

Mass of ice

Question 16

During the investigation the student stirred the crushed ice.
Suggest two reasons why

Answer 16

Box 3 and 4

Question 17

Describe the advantages and disadvantages of keeping the road clear of ice using:
- energy storage
- salt
- undersoil electrical heating

Answer 17

Energy storage advantages : - no fuel costs
- no environmental effects
Disadvantages:
- expensive to set up and maintain
- need to dig deep under road
Salt spreading advantages : - easily available
- cheap
Disadvantages:
- can damage plants
- needs to be cleaned away
Undersoil heating advantages : not dependent on weather
Disadvantages : - costly
- bad for environment