Define electromotive force (e.m.f.) of a power supply.
When connected to a 200 V supply, a lamp has a power rating of 80 W.
Calculate: (i) the current in the lamp, (ii) the resistance of the lamp's filament.
An indicator lamp is normally connected to a 6.0 V supply and carries a current of 0.40 A. The resistance of its filament is 15 Ω.
The lamp from (b) and this indicator lamp are connected in series.
Students P and Q plan to connect this series combination to a 200 V supply.
Student P says that the filament of the indicator lamp will melt and the circuit will no longer work. Student Q says that both lamps will light up and stay on.
Show, with a suitable calculation, whether student P or student Q is correct.
136 exam-style questions on CIE IGCSE Physics 4.3 Electric circuits, covering 4.3.1a Circuit diagrams and circuit components, 4.3.2a Series circuits, 4.3.2b Parallel circuits, 4.3.2c Current and potential difference in circuits, 4.3.2d Combined resistance of resistors in parallel, and 4.3.3 Action and use of circuit components. Each one has a worked solution and a mark scheme showing where the marks go.