P2- Electricity, Circuits, symbols, The National Grid, Power

Question 1

What is Current?

Answer 1

The rate of flow of charge

Question 2

What is the National Grid?

Answer 2

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

Question 3

What does the National Grid do?

Answer 3

Transfers electrical power from power stations anywhere on the grid to anywhere else on the grid where it is needed.

Question 4

What is Step-down?

Answer 4

Step-down transformers are used to supply electricity from the National Grid to consumers

Question 5

What is Step-up?

Answer 5

Used at power stations to transfer electricity to the National Grid. POTENTIAL DIFFERENCE

Question 6

What is an LDR?

Answer 6

A Light Dependent Resistor which depends on the light intensity. In the darkness the resistance is highest.

Question 7

What does an Ammeter measure?

Answer 7

Current flowing in Amps

Question 8

What is the equation linking Current, Charge and Time together?

Answer 8

Q

I X T

Question 9

What is Charge measured in?

Answer 9

Coulombs - C

Question 10

What is Current measured in?

Answer 10

Amperes -A

Question 11

What is the equation linking Current, Resistance and Potential Difference together?

Answer 11

V

I X R

Question 12

What does a Voltmeter measure?

Answer 12

Potential Difference in Volts

Question 13

What is a Thermistor?

Answer 13

Temperature Dependent Resistor

cold- resistance up
hot- resistance down

Question 14

What is a series circuit?

Answer 14

• ALL OR NOTHING
• Everything is connected together, if you remove something none of the circuit works
• The same current flows through all the components

Question 15

How do you work out the total resistance in a circuit?

Answer 15

Add all the resistance up

Question 16

What is a parallel circuit?

Answer 16

• INDEPENDENCE AND ISOLATION
• Different routes to take
• Current Splits
• If you remove one part of circuit it could still work.

Question 17

What is the colour of the LIVE wire?

Answer 17

brown

Question 18

What does the LIVE wire do?

Answer 18

Provides the alternating current (230v) from the main supply

Question 19

What is the colour of the EARTH wire?

Answer 19

Green and Yellow

Question 20

What does the EARTH wire do?

Answer 20

Protects the wiring and safety- stops the appliance casting from becoming live. Doesn’t usually carry a current- only when there’s a fault.

Question 21

What colour is the NEUTRAL wire?

Answer 21

Blue

Question 22

What does the NEUTRAL wire do?

Answer 22

Completes the circuit and carries away current. Electricity normally flows in through the LIVE wire and out through the NEUTRAL wire.

Question 23

What is the formula for Energy Transferred?

Answer 23

E= P X T

Question 24

What is Power measured in?

Answer 24

Watts