Physics Electricity Topic- Key Knowledge

Question 1

What is current?

Answer 1

The rate of the flow of charge
(How much charge passes by each second)

Question 2

What does an ammeter measure?

Answer 2

Current (Amps)

Question 3

What is voltage?

Answer 3

The energy gained or lost per unit charge
(The energy gained or lost when one coulomb of charge passes through that component)

Question 4

What does a voltmeter measure?

Answer 4

Voltage

Question 5

The total voltage across the components is equal to..

Answer 5

The voltage of the cell

Question 6

What is a diode?

Answer 6

A component that only allows current to flow in one direction

Question 7

What carries the current?

Answer 7

Delocalised electrons

Question 8

As heat increases, resistance..

Answer 8

Increases

Question 9

Plan an investigation to show how current varies with voltage for a component

Answer 9

• Vary voltage across component
  *Measure the current on the ammeter
  *measure the voltage on the voltmeter
  *Take repeat experiments and average

Question 10

–[_____]– Give the name of this component

Answer 10

Resistor

Question 11

–[_/_]– Give the name of this component

Answer 11

Variable resistor

Question 12

–[_ /]– Give the name of this component

Answer 12

Thermistor

Question 13

–(I>I)– Give the name of this component

Answer 13

Diode

Question 14

How does a fuse protect a device if there is a fault?

Answer 14

• When current exceeds fuse rating, fuse wire melts and broken circuit isolates the device

Question 15

Why are some power supplies completely cased in plastic?

Answer 15

• Acts as an electrical insulator
• Avoids electric shock

Question 16

Explain advantages of using a circuit breaker rather than a fuse.

Answer 16

• Acts faster than a fuse
• Can be reused multiple times