Question

A metal wire has a resistance of 60 Ω. It is cut into three equal lengths. Find

the equivalent resistance when two parts are connected in parallel and the third

part is in series with them.

Answer 1

Given :

Resistance = 60 ohm


Its cut into three equal parts then . R1=R2=R3=20Ω


Effective resistance of R1 and R2 when connected in parallel :

1/Rp=1/R1+1/R2
=1/20 + 1/20
=2/10
=1/10
Rp=10Ω

Effective final resistance when Rp and R3 are connected in series.

R total =Rp+R3
=10+20
=30Ω

∴The effective final resistance is 30ohms


Hope it will help you.