State what is meant by the electromotive force (e.m.f.) of an electrical power source.
When connected to a 120 V120\text{ V}120 V supply, a reading lamp has a power rating of 30 W30\text{ W}30 W.
Calculate:
the current in the lamp,
the resistance of the lamp's filament.
An indicator lamp is normally connected to a 6.0 V6.0\text{ V}6.0 V battery and carries a current of 0.25 A0.25\text{ A}0.25 A. The resistance of its filament is 24 Ω24\ \Omega24 Ω.
The reading lamp in (b) and the indicator lamp are connected in series. Students X and Y plan to connect this series combination to a 120 V120\text{ V}120 V supply.
Student X says that the filament of the indicator lamp will melt and the circuit will no longer work. Student Y says that both lamps will light up and stay on.
Show, with a suitable calculation, whether student X or student Y is correct.
52 exam-style questions on CIE IGCSE Physics 4.3.2a Series circuits. Each one has a worked solution and a mark scheme showing where the marks go.