Question

The picture tube in a particular television draws a current of 20 A. How many electrons strike the viewing screen every second?

Answer 1

As per the equation of current we will have

$i = \frac{dq}{dt}$

here we have charge

$q = Ne$

now we have from the above equation

$i = \frac{d(Ne)}{dt}$

$i = e\frac{dN}{dt}$

$20 = 1.6*10^{-19}*\frac{dN}{dt}$

$\frac{dN}{dt}= \frac{20}{1.6*10^{-19}}$

$\frac{dN}{dt}= 1.25*10^{20}electrons \: per\: second$