Topic 2

Question 1

What are the 8 magnetic stores?

Answer 1

Kinetic - moving objects
Elastic - stretched/squeezed objects
Thermal - in warm objects
Chemical - stored energy from fuel
Nuclear - radioactive objects
Magnetic
Electrostatic- between to charged objects
Gravitational potential- object that have been lifted up

Question 2

Energy efficiency can never be greater than ___

Answer 2

100%

Question 3

What three things determine the power of a circuit device.

Answer 3

-potential difference across the circuit
-current going through circuit
-the amount of energy transferred in a given time

Question 4

What is the purpose of the national grid?

Answer 4

To link power stations to consumers so they get electricity

Question 5

What are the two type of transformers used in a national grid?

Answer 5

-Step up transformer
-step down transformer

Question 6

Where are the step up transformers found in the national grid?
What do they do?

Answer 6

-step up transformers are used when connecting power stations to transmission cables
-Increase potential difference

Question 7

Where are step down transformers found in the national grid what do they do?

Answer 7

-connects transmission cables to homes
-decrease potential difference

Question 8

Why do transmission lines transfer electricity at high current?

Answer 8

High potential = low current - lower current less energy wasted = more efficient

Question 9

Why does the potential need to be decreased between transmission lines and houses?

Answer 9

-more safer (less likely to be electrocuted
-appliances only designed for 230w

Question 10

What two main factors does the amount of energy transferred by an appliance depend on?

Answer 10

-power of appliance
-how long appliance is used for