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IGCSE PHYSICS

MAINS AND MAGNETISM TEST

Page 1

These questions are about mains plugs... plug

1. Which of these is the correct description of mains electricity?

  • A). 50V a.c.
  • B). 240V a.c.
  • C). 50V d.c.
  • D). 240V d.c.

2. What is the name of the extra safety wire found in some mains plugs?

  • A). live
  • B). earth
  • C). neutral
  • D). return

3. Which of these gives the correct colours of the three wires?
Live
Earth
Neutral
A).
green/yellow
blue
brown
B).
brown
green/yellow
blue
C).
blue
green/yellow
brown
D).
brown
blue
green/yellow

4. The safety device that limits the current flow in a plug is the

  • A). fuse
  • B). cable grip
  • C). earth wire
  • D). insulation

5. Where should the earth wire be connected inside a metal toaster?

  • A). power supply
  • B). heating element
  • C). metal casing
  • D). neutral wire junction

6. Which part of the mains plug should be connected to the fuse?

  • A). live wire
  • B). earth wire
  • C). neutral wire
  • D). placed between live and neutral wires

7. This table shows electrical properties of parts of the plug. Which answer is correct?
3 pins
cable grip
plug casing
A).
conductor
insulator
insulator
B).
insulator
conductor
insulator
C).
insulator
insulator
conductor
D).
conductor
conductor
insulator

8. This hair dryer has a case made of plastic. It only needs 2 wires for safe use. hairdryerDevices like this are called

  • A). neutral devices
  • B). safety checked
  • C). current controlled
  • D). double insulated

Which one of these is the symbol for devices like this with plastic cases, only needing 2 wires?

A.
B.
C.
D.
SYMBOL1
-//-

SYMBOL3

  
SYMBOL4

10. When a current passes through a resistance wire it gets hot. Which of these appliances does NOT use this effect?

  • A). Toaster
  • B). Microwave
  • C). Hairdryer
  • D). Kettle

11. Which of these is the correct formula for electrical power?

  • A). P = IV
  • B). V = IR
  • C). V = PI
  • D). P = V/I

The table below gives some appliances and some information about their electical properties. Fill in the missing gaps and choose the correct fuse for the toaster.
Appliance
Power
Current
Voltage
Fuse
12.
Kettle
11 A
110 V
-
13.
Cordless drill
200W
50 V
-
14.
Toy car
0.6W
100 mA
-
15 + 16.
Toaster
1.2kW
240 V

 

 

  

17. Which of these answers correctly describes the current produced by mains electricity and a battery?
mains
batteries
A).
a.c.
a.c.
B).
d.c.
d.c.
C).
a.c.
d.c.
D).
d.c.
a.c.

 

The energy transferred in a circuit is given by the formula E = I V t .

Use this formula to solve the following:

  

18. What energy is transferred by a 240V kettle operating for 1 minute with a current of 6A?

  • A). 1.44kJ
  • B). 8.64kJ
  • C). 14.4kJ
  • D). 86.4kJ

19. What is the voltage ouput of a powerpack that delivers 2000 J of electrical energy to a 4A heater in 200s?

  • A). 2.5V
  • B). 10V
  • C). 20V
  • D). 500V

20. A 5Ω resistor has a p.d. of 20V across it. What heat energy is produced in the resistor per minute?

  • A). 120kJ
  • B). 2000J
  • C). 4800J
  • D). 6000J