Question

find the ratio of resistance of two copper rods x and y of lengths 30cm and 10cm respectively and having radii 2cm and 1cm respectively.

Answer 1

Answer:

3:4

Explanation:

Answer 2

Answer:

Rx / Ry = (3 /4 )

Explanation:

Resistance formula is;

R = p x L / A

Resistance for rod x will be

R = p x 30 / pi x 2^2

Rx = p 30 /4 pi

Resistance of rod x will be;

R = p x 10 / pi x 1^2

Ry = p 10 / pi

Ratio of Rx to Ry is;

Rx / Ry = (p 30 /4 pi) / (p 10 / pi)

Rx / Ry = (30 /4 ) / ( 10 )

Rx / Ry = (3 /4 )