physics topic 2- electricity

Question 1

what is an ohmic conductor?

Answer 1

a component with a fixed resistance

Question 2

what is direct current?

Answer 2

always flows in one direction and is produced by batteries

Question 3

what is alternating current?

Answer 3

is constantly changing direction

Question 4

what does an ammeter measure?

Answer 4

the current flowing through the test wire

Question 5

what does a voltmeter do?

Answer 5

measures the potential difference

Question 6

how must the voltmeter be placed in a circuit?

Answer 6

parallel

Question 7

how must the ammeter always be placed in a circuit?

Answer 7

in series

Question 8

what is the unit of measurement for electrical charge?

Answer 8

watts (w)

Question 9

what is the unit of charge?

Answer 9

coulomb (c)

Question 10

what material is a good conductor of electricity?

Answer 10

copper

Question 11

what is the ratio of voltage to current defined as?

Answer 11

resistance

Question 12

what does ohm’s law state about the flow of charge?

Answer 12

it is directly proportional to the current

Question 13

what is a diode?

Answer 13

a circuit component that only allows current to flow through it in one direction

Question 14

what is the blue wire in a plug and what does it do?

Answer 14

-neutral wire
-completes the circuit

Question 15

what is the brown wire in a plug and what does it do?

Answer 15

• live
  -provides the alternating potential difference from the mains supply

Question 16

what is the green and yellow wire?

Answer 16

-earth wire
-for safety
-stops the appliance casing from becoming live

Question 17

how do kettles transfer energy?

Answer 17

transfer energy electrically from the mains ac supply to the thermal energy store of the heating element inside the kettle

Question 18

what is the national grid?

Answer 18

a giant system of cables and transformers that covers the UK and connects power stations to consumers

Question 19

what does a build up of static electricity cause?

Answer 19

friction