2 - Electricity

Question 1

What is current

Answer 1

The rate of flow of charge

Question 2

What does resistance do

Answer 2

Slows the flow of charge down

Question 3

What is a ammeter for

Answer 3

Measures the current

Question 4

What is a mains electricity supply

Answer 4

Alternating current (a.c)

Question 5

Describe the direction of a mains electricity supply

Answer 5

Current is Constantly changing direction

Question 6

What’s the current in cells and batteries

Answer 6

Direct current (d.c)

Question 7

Describe the direction of cells and battery supply

Answer 7

Current flows in the same direction

Question 8

What happens in a series circuit if one component is moved

Answer 8

all components stop working

Question 9

What are the 3 wires in a plug

Answer 9

Live, neutral and earth

Question 10

What happens to the resistance on a LDR if more light is shone onto it

Answer 10

The resistance decreases

Question 11

What is a LDR

Answer 11

A light dependent resistor

Question 12

What happens to the resistance on a thermistor when it is heated

Answer 12

Resistance decreases

Question 13

What is a diode

Answer 13

A component which only allows current to pass in one direction

Question 14

What happens if voltage is applied in the reverse direction

Answer 14

The diode has a very high resistance and prevents any current

Question 15

What happens as the voltage across a component is increased

Answer 15

The current in the component also increases

Question 16

What is the function of a fuse

Answer 16

cuts off the flow of electricity to an appliance if the current becomes too large

Question 17

What does the earth wire do

Answer 17

Provides a low resistance path to the earth. (Safety)

Question 18

What is the purpose of double insulation?

Answer 18

• Insulation around the wires themselves

- The non-metallic case acts as a second layer of insulation

Question 19

What is electricity in metals caused by

Answer 19

A flow of electrons

Question 20

Describe electricity in metal

Answer 20

As electrons pass through the metal they collide with ions, making them vibrate

Question 21

What is an advantage of a series circuit

Answer 21

All of the components can be controlled by a single switch.

Question 22

What are the disadvantages of series circuits

Answer 22

• The components cannot be controlled separately.

- If one component breaks, the others will stop working as well.

Question 23

What are the advantages of parallel circuits

Answer 23

• The components can be individually controlled

- If one component stops working the others will continue to function.

Question 24

What does the amount of current in a series circuit depend on

Answer 24

• The voltage of the power source.

- The number (and type) of components in the circuit

Question 25

How can you test for current in a circuit ?

Answer 25

By using lamps and LEDs which light up when current passes through them

Question 26

What is current in metal caused by

Answer 26

by a flow of delocalised electrons

Question 27

What happens when two or more components are connected in series

Answer 27

• The current in each component is the same.
• The total voltage across the components is equal to the sum of individual voltages.
• The combined resistance of the components is equal to the sum of individual resistances

Question 28

What is voltage

Answer 28

The energy transferred per unit of charge passed

Question 29

High resistance =

Answer 29

Low current

Question 30

What happens at a junction?

Answer 30

Current is conserved

Question 31

Which wire connects to the fuse?

Answer 31

Live wire