P2 Electricity

Question 1

Draw the symbol for an ammeter. How must an ammeter be placed in a circuit? What is it used to measure?

Answer 1

in series, used to measure current

Question 2

Draw the symbol for a voltmeter. How must a voltmeter be placed in a circuit? What is it used to measure?

Answer 2

in parallel, used to measure potential difference

Question 3

What is difference between series and parallel circuits?

Answer 3

Series ? all components in one loop. Parallel ? components in separate loops.

Question 4

What are the units for charge?

Answer 4

Coulombs (C)

Question 5

What is current? What are the units for current?

Answer 5

Rate of flow of charge, Amps (A)

Question 6

What is potential difference? What are the units of potential difference?

Answer 6

Energy transferred per coulomb of charge, Volts (V)

Question 7

What is resistance? What are the units for resistance?

Answer 7

The opposition to the flow of current, Ohms (?)

Question 8

Why does increasing temperature increase resistance?

Answer 8

Atoms in the wire vibrate more which slows the current down

Question 9

How does current behave in a series circuit?

Answer 9

It is the same all round the circuit

Question 10

How does potential difference behave in a series circuit?

Answer 10

Potential difference is shared between the components in the circuit

Question 11

How does resistance behave in a series circuit?

Answer 11

Total resistance = add up all the resistances in the circuit

Question 12

How does current behave in a parallel circuit?

Answer 12

Current is shared between the loops of the circuit

Question 13

How does potential difference behave in a parallel circuit?

Answer 13

Potential difference is the same

Question 14

How does resistance behave in a parallel circuit?

Answer 14

The more loops there are, the lower the resistance

Question 15

Describe the relationship between current and potential difference through a resistor (at a constant temperature)

Answer 15

As current increases potential difference increases.

Question 16

What is the voltage and frequency of mains electricity in the UK?

Answer 16

230V, 50Hz

Question 17

What is the difference between direct current and alternating current (A.C.)?

Answer 17

DC goes in one direction, AC rapidly changes direction

Question 18

What is the role of a fuse in the plug?

Answer 18

The fuse is a thin piece of wire which will melt if the current is too high

Question 19

What is the National Grid?

Answer 19

A series of cables and transformers to get electricity around the country (from power stations to homes and businesses)

Question 20

What do step up and step down transformers do?

Answer 20

Step up the voltage to reduce energy loss when electricity goes through the cables. Step down the voltage to make it safe in our homes.

Question 21

Draw the current-potential different graph for an ohmic resistor.

Answer 21

Question 22

Draw a resistor

Answer 22

Question 23

Draw a lamp

Answer 23

Question 24

Draw the symbol for a cell (electrical)

Answer 24