Domestic Uses and Safety (2) Flashcards
What happens to the energy wasted by the light bulb?
It is transferred to the surroundings by heating
Suggest why the homeowner is likely to choose LED bulbs
Uses less power and lasts longer. 1 LED costs £16 and 40 filament bulbs cost £80
Suggest why it is important to confirm this information independently
To avoid bias
State one factor, other than efficiency, that is important when considering the choice of a bulb for lightning in the home
Availability of bulbs
What colour is the insulation around the wire to the live pan inside the plug?
Brown
Why does the hairdryer not need an earth wire?
Outside case is an insulator
Which switch or switches have to be ON to make:
(1) only the fan work
(2) heater 2 work
(1) S
(2) S and S
The heaters can only be switched on when the fan is also switched on.
Explain why
S must be on for the heater to work so S switches on
Evaluate in terms of cost and energy efficiency, the use of the two types of light bulb
- 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
A fuse is connected in the _______ wire
RCCBs are sometimes preferred to fuses because they ___________
The two wires are the _______ and _________
- live
- react faster
- live and neutral
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
Ammeter to measure current and variable resistor to vary current
Suggest two changes that would allow lower values of current to be used in this investigation
- use smaller masses
- move mass closer to pivot
The system could work well because the road surface is black.
Suggest why
Black is a good absorber of infrared radiation
What is meant by specific latent heat of fusion?
Amount of energy required to change the state of a substance from solid to liquid with no change in temperature
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
Mass of ice
During the investigation the student stirred the crushed ice.
Suggest two reasons why
Box 3 and 4
Describe the advantages and disadvantages of keeping the road clear of ice using:
- energy storage
- salt
- undersoil electrical heating
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
