Question

A wire of resistance 12Ω/m is bent to form a complete a circle of radius 10 cm. The resistance between its two diametrically opposite , A and B is ?

Answer 1

Answer:

3 Ω

Explanation:

Resistance = 12Ω (Since its resistance and not resistivity, I changed a question little bit)

The lenth of the wire will be 2πr = 2×5Π = 10πcm

Resistivity of the wire will be ₱ = 12/10π Ω/cm

When wire is bent into a circle and the resistance between two diametrically opposite points is measured, wire seems to be in parallel arrangement. So,

1/Req = 1/R + 1/R

1/Req = 2/R

Req = R/2

Req = ₱(length)/2

Req = 12/10π × 5π/2

Req = 3 Ω