PHYSICS · Single correct · A Level · Physics · Electricity · Electricity
Problem
A wire of length L is used in an electric heater. When the potential difference across the wire is 200 V, the power transferred in the wire is 500 W. A second wire is made from the same metal and has the same cross-sectional area. When a potential difference of 400 V is applied across the second wire, the power transferred is 2000 W.
What is the length of the second wire?
(A) 4L
(B) 2L
(C) L
(D) 2L