4.2.4 P1 Energy transfers (will come up)

Question 1

What 2 main factors does the amount of energy transferred by an appliance depend on

Answer 1

How long the appliance is being used for

The power of the appliance

Question 2

Describe the energy transfers in a battery powered torch

Answer 2

Battery converts chemical energy into electrical energy

Bulb converts electrical energy into light as well as waste energy in the form of heat

Question 3

Describe the energy transfers in a battery powered motor

Answer 3

Battery converts chemical energy into electrical energy

Motor converts electrical energy into kinetic energy as well as waste energy in the form of heating due to friction

Question 4

What is the purpose of the National Grid

Answer 4

To link power stations to consumers so that they have access to a source of electricity

Question 5

What are the 2 types of transformers used in the National Grid

Answer 5

Step-Up transformers

Step-Down transformers

Question 6

Where are step-up transformers found in the National Grid and what do they do

Answer 6

They are used when connecting power stations to transmission cables
They increase the potential difference

Question 7

Where are step-down transformers found in the National Grid and what do they do

Answer 7

They are used in connecting transmission cables to domestic buildings (like houses)
They decrease the potential difference

Question 8

Why do transmission lines transfer electricity at high potentials

Answer 8

A high potential results in a low current
The lower the current the less energy that is wasted as heat
Therefore it is more efficient

Question 9

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

Answer 9

Lower potentials are safer for domestic use and reduces the likelihood of severe electrocution
Appliances are designed for 230V