Question

A metallic wire of length L, area of cross section A and resistivity ρ has resistance

R. What will be the resistance and resistivity of another wire of same material, if

its length is 3L and area is A/3?​

Answer 1

Answer:

Explanation:

The resistance of a material works on an equation stated below.

R= ρ l/A

Where,

R- resistance

ρ - resistivity

l - length of specimen

A - cross sectional area of specimen

Now, of a wire with length l and radius r, suppose resistance is R.

But fir a wire wuth same material, same length and double radius (2r) will be different because,

For the same material, the resistivity remains the same. ρ

Length is the same.l

Radius is double, thus making cross sectional area four times of the original radius area(A). Thus, area will be 4A.

R2= ρ l/4A

This makes the resistance of second wire one fourth of the resistance of first wire.

They can not be the same.