An electorn moves in a circle of radius 10cm with a constant speed of `4.0xx10^(6)ms^(-1)`.Find the electric current at a point on the circle.

Explanation

Consider a point A on the circle. The electron crosses this point once in every revolution. The number of revolutions made by electron in one second is
`n=(v)/(2pir)=(4xx10^(6))/(2npixx10 xx10^(-2))=(2)/(pi)xx10^(7)` rot./sec.
`therefore` current `I=("ne")/(t)=(2)/(pi)xx10^(7)xx1.6xx10^(-19) (because t=1"sec".)`
`=(3.2)/(pi)xx10^(-12)=1xx10^(-12)A`