Electricity

Question 1

What is electrical current?

Answer 1

Current is the flow of electric charge past a point every second

Question 2

What is the relationship between charge, current and time?

Answer 2

Current is the number of coulombs of charge that passes a point every second

Question 3

What is current like in a series circuit?

Answer 3

Current is the same at every point in a series circuit

Question 4

What is current like in a parallel circuit?

Answer 4

The current in the branches adds up to the current in the supply

Question 5

What is voltage (potential difference)?

Answer 5

Voltage is a measure of the electrical energy given to each coulomb of charge by the supply. This can be seen by the formula:
V=Ew
Q

Question 6

What is voltage like in a series circuit?

Answer 6

The voltage across each component added up is equal to the voltage across the supply

Question 7

What is voltage like in a parallel circuit?

Answer 7

The voltage across each component is the same as the voltage across the supply

Question 8

What do resistors do in a circuit?

Answer 8

Resistors decrease the current in a circuit

Question 9

What does a fuse do?

Answer 9

The fuse in a plug protects the flex from too much current. The fuse melts if too high a current passes through it

Question 10

What are the formulae for electrical power?

Answer 10

P = I x V
P = I^2R
P = V^2
R

Question 11

What power rating does the appliance need to have to use a 3A fuse?

Answer 11

Under 720W

Question 12

What power rating does the appliance need to have to use a 13A fuse?

Answer 12

720W or over

Question 13

What do A. C. AND D. C. stand for?

Answer 13

Alternating current

Direct current

Question 14

Does electricity pass through insulators or conductors?

Answer 14

Conductors

Question 15

What happens to the resistance of a resistor when it heats up?

Answer 15

The resistance increases

Question 16

What happens to the resistance in an LDR when the light intensity is increased?

Answer 16

The resistance decreases (LURD)

Question 17

What happens to the resistance in a thermistor when the temperature is increased?

Answer 17

The resistance decreases (TURD)

Question 18

Why does the current only flow in one direction in a diode?

Answer 18

There is a very high resistance in one direction

Question 19

What does a capacitor do?

Answer 19

A capacitor stores charge

Question 20

Describe direct current (D. C.)

Answer 20

Direct current flows in one direction around a circuit

Question 21

Describe alternating current (A. C.)

Answer 21

Alternating current is where the current repeatedly changes direction. The rate of change is measured in Hertz (Hz)

Question 22

Describe what a potential divider is and what it does

Answer 22

A potential divider consists of a pair of resistors. It divides the voltage in a circuit and the higher the resistance the bigger the voltage across it

Question 23

What is meant by power rating?

Answer 23

Power is the amount of energy transferred or converted every second