Question

Dimensions of a block are `1 cm xx 1 cm xx 100 cm`. If specific resistance of its material is `3 xx 10^(-7)`ohm-m, then the resistance between the opposite rectangular faces is
A. `3 xx 10^-9 ohm`
B. `3 xx 10^-7 ohm`
C. `3 xx 10^-5 ohm`
D. `3 xx 10^-3 ohm`

Answer 1

Correct Answer - B
Between rectangular faces, `l = 1 cm, A = 100 cm^2`
`R = (rho l)/(A) = (3 xx 10^-7 xx 1)/(100 xx 10^-2) = 3 xx 10^-7 ohm`.