Question

If the Resistance of conducting wire P is four times the resistance of conducting wire Q then the ratio of cross sectional areas of wire is what

Answer 1

Hey dear,

● Answer -
Ap : Aq = 1 : 4

● Explaination -
# Given -
Rp = 4Rq

# Solution -
You didn't say anything about length of wires so I'll assume both wires are made of same material and have same length.

Resistance of wire P,
Rp = ρl / Ap

Resistance of wire Q,
Rq = ρl / Aq

Taking ratio,
Rp/Rq = (ρl/Ap) / (ρl/Aq)
4 = Aq / Ap
Aq / Aq = 1/4

Therefore, ratio of cross sectional areas is 1:4.

Hope this helps...