Question

A 2m long wire with a radius of 1mm has a resistance of 16Ω. What is the resistance of the same type of wire which is 4m long and has a radius of 2mm?
A) 4 Ω
B) 8 Ω
C) 16 Ω
D) 32 Ω

Answer 1

Answer:

B) 8 ohm

Explanation:

Since

R=¶L/A

Hence,

R1/R2 = L1*A2/A1*L2

16/R2 = 2*(2*10^-3)^2 / (10*-3)^2*4

16/R2 = 8/4

R2 = 16/2

R2 = 8 ohm