Question

Two wires A and B are of equal length, different cross sectional areas and made of same metal. if the resistance of wire A is four times the resistance of wire B. Calculate:
1) The ratio of the cross sectional areas of the wires.
2) The ratio of the radii of the wire.

Answer 1

Answer:

1)A1:A2=4:1

By using the formula of resistance

Answer 2

Since we know that

R = resistivity *length/area .

so

length is proportional to R

area is inversely proportional to square root of Area

let A1 and A2 be area

A1/A2 = sqrtx^2/x^2/4

A1/A2 = 2/1= 2:1✔️

ratio of radius

x1/x2 = 1/2 = 1:2 ✔️