Question

a metallic wire having length 1km and the amount of current 60 Ampere is flowing through it find out the total momentum of free electron​

Answer 1

A metallic wire having length 1 km and the the amount of current 60A is flowing through it.

To find : The total momentum of free electron.

solution : we know, momentum is the product of mass and velocity. i.e., P = mv

here m is mass and v is velocity.

v = l/t = l/(q/i) = il/q

so, momentum, P = mil/q

here q = charge on electron = 1.6 × 10^-19 C

m = mass of electron = 9.1 × 10^-31 Kg

i = current = 60 A

l = length of wire = 1000 m

so, P = (9.1 × 10^-31 × 60 × 1000)/(1.6 × 10^-19)

= (9.1 × 60 × 10^-28)/(1.6 × 10^-19)

= 341.25 × 10^-9

= 3.4125 × 10^-7 Kgm/s

Therefore the momentum of free electron is 3.4125 × 10^-7 Kgm/s