### GCSE Physics

Energy
Forces
Forces and Motion
Waves in Matter
Electricity
Magnetism and Electromagnetism
Particle Model of Matter
Atomic Structure
Space Physics

# Electrical Power and Energy Transfers in Appliances

## Electrical Power

Power measures the rate at which energy is transferred by a device, often expressed in terms of energy per second. This means that a more powerful device will transfer more energy over a period of time.

We can calculate the power transferred in a device or appliance using the potential difference and current. The equation is:

However, if we don’t know the potential difference value, we can also calculate power using the current and resistance of the device or appliance.

• P = Power in watts (W)
• V = Potential difference in volts (V)
• I = Current in amperes (A)
• R = Resistance in ohms (Ω)

## Energy Transfers in Appliances

Every electrical appliance transfers energy from one store to another. Whenever charge flows in a circuit, electrical work is done.

How much energy is transferred by an electrical appliance depends on:

• The time the appliance is on for
• The power of the appliance

We can calculate the energy transferred by an appliance using the equation:

• E = Energy transferred in joules (J)
• P = Power in watts (W)
• t = Time in seconds (s)
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