Question

Q.) Two copper wire of length l and 2l have radius r and 2r respectively.

a.) 1:2 b.) 2:1

c.) 1:1 d.) 1:3​

Answer 1

a will the answer of ratio of resistance of wire one to wire two

Answer 2

Answer:

1 : 1

Explanation:

we know,

R = p l/A

where R is resistance, l is length of wire, A is cross sectional area and  p  is specific resistance.

you should remember that, for same material specific resistance remains same. it is material property. specific resistance doesn't change when we change length and cross sectional area of same material wire.

so, ratio of specific resistance is 1 : 1.

[ note :- I know, you will think if R = pl/A  then p = RA/l, , but it doesn't apply in case of same material. you should apply for different material ]