Answer:
0.20 m.
Explanation:
Given: R = 30 Ω and L = 1 m
Resistance of 1m wire is R = V/I = 30Ω/0.1A
6Ω resistor will have the same voltage drop across it as 1m wire, so we require I to be 6A. Therefore, the required length of wire is:
L = (6A)/(30Ω) = 0.2m