Question

Dimensions of a block are `1 cm xx 1 cm xx 10 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
(b) Length `l = 1 cm = 10^(-2) m`
Area of cross-section `A = 1 cm xx 100 cm`
`= 100 cm^(2) = 10^(2) m^(2)`
Resistance `R = 3 xx 10^(-7) xx (10^(-2))/(10^(-2)) = 3 xx 10^(-7) Omega`