Question

A uniform wire of resistance 2.20 ohm has a length of the similar wire which connected in parallel with the 2 m long wire, will give a resistance of 2 ohm

Answer 1

Hey dear,

● Answer -

l2 = 20 m

◆ Explaination -

# Given -

R1 = 2.2 ohm

l1 = 2 ohm

Rp = 2 ohm

# Explanation -

Equivalent resistance of two wires connected in parallel is calculated as -

Rp = R1.R2 / (R1+R2)

2 = 2.2 × R2 / (2.2 + R2)

4.4 + 2R2 = 2.2R2

R2 = 4.4/0.2

R2 = 22 ohm

Both wires are made from same material. Thus, resistivity will be same.

ρ = R1.A/l1 = R2.A/l2

R1/l1 = R2/l2

l2 = R2.l1/R1

l2 = 22 × 2 / 2.2

l2 = 20 m

Therefore, length of second wire is 20 m.

Thanks for asking..