The Usefulness of Electrical Appliances

Question 1

What is the power of an appliance?

Answer 1

The amount of energy it transfers in a given time frame.

Question 2

What is the formula for energy transfer in joules?

Answer 2

J = W x s

J = Energy Transferred (Joules)

W= Power (Watts)

s= Time (seconds)

Question 3

What is the formula for energy transfer in kilowatt-hours?

Answer 3

kWh = kW x h

kWh = energy transferred (kilowatt hours)

kW= power (kW)

h= Time (hours)

Question 4

Why would one work in kilowatt-hours?

Answer 4

If we are dealing with large amounts of electricity.

Question 5

What is the formula for the cost of electricity?

Answer 5

Cost = kWh used x price per kWh

Question 6

How can you work out how much energy has been used from an electricity metre?

Answer 6

Deduct the old reading from the new reading.

Question 7

What should you consider when comparing rival products?

Answer 7

• Cost effectiveness
• Energy efficiency
• Practicality

Question 8

How can having a limited access to electricity affect road safety?

Answer 8

Electric lighting makes travelling at night safer.

Question 9

What is the issue with LEDCs not having fridges?

Answer 9

They are used to keep vaccines cool. Without them any vaccinations become very difficult.

Question 10

How can hospitals in LEDCs suffer from having a limited electricity supply?

Answer 10

Hospitals rely heavily on electrical machinery like X-ray Machines. Without access to such machines diagnosis an treatment of patients is very difficult.

Question 11

How can having a limited electricity supply affect communication?

Answer 11

It restricts use of Internet and phones making it difficult to send and receive information.