A $20\,\text{V}$ d.c. power supply is connected to a circuit made up of five resistors L, M, N, P and Q. Across L there is a potential drop of $7\,\text{V}$, and across N there is an additional potential drop of $4\,\text{V}$. What are the potential drops across M, P and Q?
Physics 9702 · AS & A Level · Kirchhoff's laws