Chapter 6: Electricity and Magnetism

Renewable energy sources

Energy sources that can be replaced continually and never deplete.

Non-renewable energy sources

Energy sources that cannot be replaced and will deplete.

Bakun hydroelectric power station

Located in Sarawak and uses hydro energy.

Sultan Azlan Shah power station

Located in Manjung, Perak and uses coal.

Generator mechanism

Generates electricity when wire or magnetic motion cuts magnetic field lines.

Thermal power station energy change

Chemical energy to heat energy to kinetic energy to electrical energy.

Hydroelectric power station energy change

Gravitational potential energy to kinetic energy to electrical energy.

Direct current (DC)

Electric current flowing in one direction only.

Alternating current (AC)

Electric current flowing in constantly reversing directions.

Cathode Ray Oscilloscope (C.R.O.)

Device used to indicate graph shapes, current direction, and voltage change.

Step-up transformer

Primary voltage is lower than secondary voltage; fewer primary coils.

Step-down transformer

Primary voltage is higher than secondary voltage; more primary coils.

Transformer formula

Vp / Vs = Np / Ns

National Grid transmission voltages

132 kV, 275 kV, or 500 kV for long-distance transport.

Residential voltage in Malaysia

240 V supplied to office, business, and residential areas.

Single-phase wiring

Suitable for electricity consumption not exceeding 10 kW or 50 A.

Three-phase wiring

Suitable for electricity consumption of more than 10 kW or 50 A.

Earth leakage circuit breaker (ELCB)

Cuts off the circuit when excessive current flows.

Fuse function

Melts when current exceeds the rated value to protect circuits and appliances.

Energy efficiency formula

(Useful energy output divided by energy input supplied) times 100%

Kilowatt-hour (kWh)

Unit of electrical energy equal to 1 kilowatt used for 1 hour (1 kWh = 1 unit).