A smart speaker is connected to the mains electricity supply using a power adapter.
The power input to the smart speaker circuit is 6.0 W6.0\text{ W}6.0 W. The potential difference across this circuit is 15 V15\text{ V}15 V. Calculate the current in the smart speaker circuit.
current=____________________ A \text{current} = \text{\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ A} current=____________________ AThe energy used by the smart speaker each hour is 0.0080 kWh0.0080\text{ kWh}0.0080 kWh. One unit (kWh\text{kWh}kWh) of electrical energy costs 40 cents40\text{ cents}40 cents. Calculate the cost of using the smart speaker for 25 hours25\text{ hours}25 hours.
cost=____________________ cents \text{cost} = \text{\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ cents} cost=____________________ centsThe power adapter contains a transformer. The number of turns NpN_{\text{p}}Np on the primary coil of the transformer is 460046004600. The primary voltage VpV_{\text{p}}Vp supplied to the transformer is 230 V230\text{ V}230 V. The secondary voltage VsV_{\text{s}}Vs of the transformer is 15 V15\text{ V}15 V. Calculate the number of turns NsN_{\text{s}}Ns on the secondary coil of the transformer.
number of turns Ns=____________________ \text{number of turns } N_{\text{s}} = \text{\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_} number of turns Ns=____________________The mains plug for the power adapter includes a fuse that protects the device. Explain how a fuse works.
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.