Physics (AS & A Level) · May / June 2018 · Paper 13 · Question 38

In the circuit shown, XY is a length L of uniform resistance wire. A potential difference is applied across XY. R_1 and R_2 are unknown resistors. J is a sliding contact that joins the junction of R_1 and R_2 to points on XY through a lamp S. J is moved along XY to a point at which the lamp is off. This point is at a distance x from X. The potential difference across R_1 is V_1 and the potential difference across R_2 is V_2. What is the value of the ratio V_1/V_2?

1. AL/x
2. Bx/L
3. C(L - x)/x
4. Dx/(L - x)

As printed in the paper