Electrical Appliances

How do we choose an electrical appliance for a particular job?

Appliances are designed for a particular purpose, and should not waste the minimum of energy.

Why are electrical appliances so useful?

Electrical appliances transfer electrical energy into useful energy.

Rearrange this formula to calculate the energy used by an appliance.

Energy (Joules) = Power (Watts) × Time (seconds) J=W × s

Give examples of how electrical appliances are used.

Lighting Heating Moving Creating visual images Creating sound

What is the formula for calculating the power of an appliance?

Power (in Watts) is Energy (Joules) divided by time (seconds) so W = J divided by s

What do we mean by power?

Power is rate of energy transfer

What formula calculates the efficiency of an appliance in terms of power?

Power out divided by power in × 100

What costs need to be considered when working out cost effectiveness

Purchase costs Running costs Environmental costs

what is the kilowatt hour?

The kilowatt hour is the energy supplied to a 1kw appliance in 1 hour

How do we calculate the cost of mains electricity?

Total cost = number of kWh used ×cost per kWh

What is meant by cost effectiveness?

Value for money