Electricity

Question 1

State the charge and relative mass of protons, neutrons and electrons

Answer 1

Protons = (charge) +1, (relative mass) 1
Neutrons = (charge) 0, (relative mass) 1
Electrons = (charge) -1, (relative mass) 1/2000

Question 2

Define Conductor

Answer 2

Material that allows the flow of electric current

Question 3

Define Insulator

Answer 3

Material that doesn’t allow the flow of electric current

Question 4

What does LDR stand for?

Answer 4

Light Dependent Resistor

Question 5

Which direction does convectional current go in?

Answer 5

+ to -

Question 6

Which direction do electrons go?

Answer 6

– to +

Question 7

State the unit for energy

Answer 7

Joules (J)

Question 8

State the unit for Power

Answer 8

Watts (W)
(same as joules per second (J/s))

Question 9

State the formula for power

Answer 9

P = E/T
(Power = Energy used/Time)

Question 10

AC

Answer 10

Alternating Current
A current which is constantly changing in direction

Question 11

Name a source of AC

Answer 11

Mains Electricity
50Hz (voltage changes 50 times per second)
230V

Question 12

DC

Answer 12

Direct Current
A current that is always flowing in one direction

Question 13

Name of source of DC

Answer 13

Cells or Batteries

Question 14

Name the 3 wires

Answer 14

Neutral
Live
Earth

Question 15

What is a neutral wire?

Answer 15

A wire that completes the circuit to the power station
Is kept at 0 volts by the electricity company
Blue

Question 16

What is a live wire?

Answer 16

A wire that carries the high voltage
Connects the appliance to generators at the power station
Brown

Question 17

What is an earth wire?

Answer 17

A wire needed to earth appliances with a metal case.
Connects the appliance to the ground outside the building.
This makes it safer to touch the appliance if it developed a fault.

Question 18

What is a fuse?

Answer 18

A safety device containing a thin metal wire that melts if the current is too high

Question 19

What is a RCCB?

Answer 19

Residual Current Circuit Breakers
They detect a difference in current between live and neutral wires.
They use electromagnets to break the circuit if the current difference becomes too large.

Question 20

Current

Answer 20

The flow of electrical charge

Question 21

Which 2 things are needed for a current to flow through an electrical component?

Answer 21

A potential difference across the component
A complete circuit

Question 22

What is a voltmeter?

It measures what in what and how is it connected

Answer 22

Connected in parallel
Measure PD in volts

Question 23

Ammeter

Answer 23

Connected in series
Measure current in amps

Question 24

State the formula for charge

Answer 24

Q = It
Charge = Current x time

Question 25

State the formula for energy

Answer 25

E = QV Energy = Charge x voltage

Question 26

Give another name for Potential Difference

Answer 26

Voltage

Question 27

What is a series circuit?

Answer 27

A circuit with only one loop

Question 28

What is a parallel circuit?

Answer 28

A circuit with two or more loops

Question 29

What is the rule for current in a series circuit?

Answer 29

It's the same everywhere

Question 30

What is the rule for current in a parallel circuit?

Answer 30

It splits up

Question 31

What is the rule for PD in a series circuit?

Answer 31

It splits up

Question 32

What is the rule for PD in a parallel circuit?

Answer 32

It's the same everywhere

Question 33

What is the rule for resistance in a series circuit?

Answer 33

Add resistances to find the total

Question 34

What is the rule for resistance in a parallel circuit?

Answer 34

Total resistance is less than the lowest resistor

Question 35

What are the differences between DC and AC?

Answer 35

DC is always in the same direction and always has the same magnitude. AC changes direction and changes magnitude.

Question 36

Do convectional current and electrons go in the same direction?

Answer 36

No Convectional current goes from + to - whereas Electrons go from - to +