Question

A tv set shoots out a beam of electrons. The beam current is 10 A. How many electrons strike the tv screen in a minute

Answer 1

Charge Striking the screen per minute = 6.0 × 10⁻⁴ C. Hence, 6.25 × 10¹³ electrons strike the TV screen in each second and 6.0 × 10⁻⁴ C charge strikes the screen in a minute.

Answer 2

The charge of an electron is 1.6 x 10-19C.

Thus for a current of 10 mA, the charge going to screen in one scond is 10 mC

thus number of electrons, n = (10 x 10-3)/(1.6 x 10-19) = 6.25 x 1016

In a minute charge striking the screen = 10 * 60 = 600 mC