Electricity

Question 1

Unit for:
Current
Charge
Resistance
Time
Potential difference
Power

Answer 1

• Ampere (A)
• Coulomb (C)
• Ohms (Ω)
• Seconds (s)
• Volts (V)
• Watts (W)

Question 2

What is a fuse + circuit breaker used for?

Answer 2

• Melts when the current is too high —> breaking the circuit
• Breaks the circuit if current is too high

Question 3

What is insulation and why is it used

Answer 3

• A material that doesn’t conduct electricity
• Used so person cannot touch live wire

Question 4

What is double insulation and why is it used

Answer 4

• Both the wires inside the device and the outer case of the device are insulated
• So no chances of electrocution

Question 5

What does an earth wire provide

Answer 5

• Earthing provides a low resistance path for current to the earth
• It connects to metal casing

Question 6

What can resistance transfer?

Types of energy does it transfer + how is it useful in domestic applianc

Answer 6

• Resistance can cause the transfer or electrical energy —> heat energy
• Eg electrical heaters contain a lot of resistors to ensure to ensure high resistance; lots of heat energy produced

Question 7

Advantages of parallel circuit

Answer 7

• If one component breaks, the current can still flow through the other parts of the circuit
• Components can be switched on and off individually
• Current of independant components add up to total current
• Voltage is same everywhere

Question 8

Advantages of series circuit

Answer 8

• Fewer wires, cheaper + easy to assemble
• Uses less power
• Voltage of independant components add up to total voltage
• Current stays the same everywhere

Question 9

in an LDR and thermistor…

As … Increase,

Answer 9

• As light increases, resistance decreases
• As temp increases, resistance decreases

Question 10

What is voltage?

Answer 10

Energy transferred per coulomb of charge passed