Question

A current of 7.04 A flows through a wire of radius 4.67 cm. What is the surface current in A/m.

Answer 1

Given that,

Length l=0.2m

Area A=1mm

2

Voltage V=4v

Electron mobility μ=4.5×10

−6

m

2

/s

Charge e=1.6×10

−19

C

Number density n=8.5×10

−18

m

3

We know that,

The current flows is

I=neAv

d

I=neAμ

l

V

I=8.5×10

28

×1.6×10

−19

×10

−6

×4.5×10

−6

×

0.2

4

I=1224×10

−3

A

I=1.22A

Hence, the current is 1.22 A