(153) GCSE Physics - National Grid

What is the national grid?

The national grid is a giant network of transformers and wires that distributes electricity across the country.

How is electricity generated in the UK?

Electricity is generated from a range of sources, primarily power stations.

What process do power stations use to generate electricity?

Power stations generate heat and convert that thermal energy into electrical energy.

When does electricity demand typically peak?

Electricity demand generally peaks in the late afternoon and evening.

Why do power stations run at below maximum power output?

Power stations need spare capacity to cope with surges in demand.

What equation relates power, voltage, and current?

Power is equal to voltage times current.

What happens when high current flows through a wire?

It generates heat due to the resistance in the wire, leading to energy loss.

How does the national grid minimize energy loss during electricity transmission?

By keeping the current low and increasing the voltage with step-up transformers.

What voltage do step-up transformers increase electricity to?

Step-up transformers increase the voltage to around 400,000 volts.

What do step-down transformers do?

They lower the voltage back down to around 230 volts before reaching homes.

Why is it important to lower the voltage before electricity reaches homes?

High voltages are dangerous and could damage household appliances.

What components make up the national grid?

The national grid is made up of transformers, wires, and pylons.