Question

A wire has a resistance 12 Ω. It is bent in the form of a circle. The effective resistance between two points on any diameter is(a) 6 Ω(b) 3 Ω(c) 12 Ω(d) 24 Ω

Answer 1

From Ohm Law,

i = E/ (R + r )

Putting the Values,

2.3 = 18 (30 + r)

2.3 = 1830r

30r = 18 2.3

r = 18/2.3 × 1/30

r = 3/11.5

Internal resistance of cell is 3/11.5 Q