A smart home security camera is powered via an electrical adapter connected to the mains supply.
The power input to the camera circuit is 8.0 W8.0\text{ W}8.0 W. The potential difference across the camera circuit is 16 V16\text{ V}16 V.
Calculate the current in the camera circuit.
The energy used by the camera each hour is 0.012 kWh0.012\text{ kWh}0.012 kWh. One unit (1 kWh1\text{ kWh}1 kWh) of electrical energy costs 25 cents.
Calculate the cost of using the camera continuously for 24 hours.
The adapter contains a step-down transformer. The number of turns NpN_pNp on the primary coil of the transformer is 4500. The primary voltage VpV_pVp applied to the transformer is 240 V240\text{ V}240 V and the secondary voltage VsV_sVs is 16 V16\text{ V}16 V.
Calculate the number of turns NsN_sNs on the secondary coil of the transformer.
The plug for the adapter circuit includes a fuse to protect the circuit and device. Explain how a fuse works to protect the circuit.
69 exam-style questions on CIE IGCSE Physics 4.2.5 Electrical energy and electrical power. Each one has a worked solution and a mark scheme showing where the marks go.