ES

Question 1

definition of electric current (I)

Answer 1

rate at which electric charge flows

Question 2

how does current flow ( positive, negative)

Answer 2

positive terminal to negative terminal

Question 3

SI unit of electric current

Answer 3

ampere

Question 4

what is an ammeter

Answer 4

used to measure electric current

Question 5

how to connect ammeter to circuit

Answer 5

positive terminal of ammeter must connect to positive terminal of battery

Question 6

definition of potential difference

Answer 6

potential diff btwn 2 points in an electric circuit is the amt of energy needed to move a unit charge from one point to another

Question 7

how to connect voltmeter to circuit

Answer 7

voltmeter must be parallel to the component measured
positive terminal of voltmeter must connect to positive terminal of battery

Question 8

what is the SI unit of potential difference

Answer 8

volt (V)

Question 9

definition of Resistance

Answer 9

measure of how much the component opposes the flow of electric current

Question 10

SI unit for resistance

Answer 10

ohm

Question 10

formula for V, I, R

Answer 10

V = I x R, R=V / I

Question 11

what happens to brightness of bulbs if more bulbs are added in series

Answer 11

effective resistance of bulb increases, current flowing through lamps decreases, brightness of bulbs decreases

Question 12

what is the relationship of electric current in series

Answer 12

I = I1 = I2 = I3

Question 13

what is the relationship of potential difference in series

Answer 13

V = V1 + V2 + V3

Question 14

what is the relationship of resistance in series

Answer 14

R = R1+R2+R3

Question 15

what is the relationship of electric current in parallel

Answer 15

I = I1+I2+I3

Question 16

what is the relationship of potential difference in parallel

Answer 16

V = V1 = V2

Question 17

what is the relationship of resistance in parallel

Answer 17

1/R = 1/R1 + 1/R2 + 1/R3
then flip fraction over
(eg 7/10 to 10/7)

Question 18

what happens when more resistors are added in parallel

Answer 18

effective resistance decreases, total current drawn increases

Question 19

disadvantages of series

Answer 19

• cant turn lights off / on independently
• if a bulb fused, all bulbs will not light up
• lights will be dimmer than in parallel

Question 20

formula for power

Answer 20

power (W) = energy converted (J)/ time taken (s)

Question 21

what is the SI unit for power

Answer 21

watt (W)

Question 22

formula for amt of energy used

Answer 22

energy (J) = Power (W) x Time (s)

Question 23

formula for electric bills
( used as large amt of energy is produced)

Answer 23

energy (kWh) = Power (kW) x Time (h)

Question 24

features of the live wire

Answer 24

brown colour, delivers current to appliance

Question 25

features of the neutral wire

Answer 25

blue colour, complete circuit by providing return path to supply

Question 26

features of earth wire

Answer 26

yellow and green, provide path for low electrical resistance, extra current will flow directly to the ground

Question 27

features of a fuse

Answer 27

prevents excessive current flow by switching off appliance if have large current flow

Question 28

what is a short circuit

Answer 28

unintentional bypass in the circuit, large electric current can generate enough heat to start a fire