6.2.4 Energy transfers

Question 1

Everyday electrical appliances are designed to?

Answer 1

bring about energy transfers

Question 2

The amount of energy an appliance transfers depends on?

Answer 2

how long the appliance is switched on for and the power of the appliance

Question 3

when charge flows in a circuit?

Answer 3

Work is done

Question 4

blenders and fans are designed for?

Answer 4

-designed for movement
powered by electrical energy which is transferred into the kinetic energy of electric motors

Question 5

irons and kettles are designed to get hot.what do they do?

Answer 5

use electrical energy from the mains but transfer it into thermal energy

Question 6

hair dryer and washing machine

Answer 6

both use electrical energy and transfer it to kinetic energy of electrical motors + thermal energy

Question 7

what is the national grid?

Answer 7

The National Grid is a system of cables and transformers linking
power stations to consumers.

Question 8

what is the national grid used for?

Answer 8

Electrical power is transferred from power stations to consumers
using the National Grid.

Question 9

what are step-up transformers used for?

Answer 9

Step-up transformers are used to increase the potential difference
from the power station to the transmission cables

Question 10

what are step-down transformers used for?

Answer 10

step-down
transformers are used to decrease, to a much lower value, the
the potential difference for domestic use.

Question 11

why is the National Grid system is
an efficient way to transfer energy?

Answer 11

due to the use of step-up and step-down transformers
High potential difference means low current (less energy dissipated) for the same power
Low potential difference means high current (more energy dissipated) for the same power

Question 12

less energy is lost in the power cables when?

Answer 12

the potential difference is very high