Question

Two wires A and B of the same material, having radii in the ratio 1:2 and carry current in the ratio 4:1.find the ratio of drift speed of electron in A and B

Answer 1

Answer:

16:1

Explanation:

I = neav

where I - current

n - carrier per unit volume

a - csa

v - drift velocity

Radius of 1st wire = r

Radius of 2nd wire = 2r

Current in 1st wire = I

Current in 2nd wire = 4I

1st wire area = pi . r²

2nd wire area = pi . (2r)²

I₁/I₂ = a₁v₁/a₂v₂

Therefore, 4I/I = pi/r² v₁ / 4 pi. r² . v₂

Therefore, v₁/v₂ = 16/1

Answer 2

See the attachment...

Thank you