Question

A metal wire has a reistance of 60ohm . Is cut into three equal lengths. Find
the equivalent resistance when two parts are connected in parallel and the third part 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.
Rtotal =Rp+R3
=10+20
=30Ω

∴The effective final resistance is 30ohms