Question

the specific resistance of manganese is 50 ×10^-8 ohm m. the resistance of a cube of length 50 cm between its two opposite face will be
[1] 10^-6
[2] 2.5× 10^-6
[3] 10^-8
[4] 5×10^-4

Answer 1

Answer:

We know that

Rho = RA/L

REARRANGING

R = RHO X L/A

HERE RHO = 50 X 10-8 ohm m

L = 50cm = 0.5m

Area of wire = 0.5 X 0.5

So R = 50 X 10-8 X 0.5 / 0.5 X 0.5

= 50 X 10-8 / 0.5

=50 X 10-8 X 10 / 5

=10 X 10-8 X 10

= 10^2 X 10-8

=10-6 (A) answer