Question

In a particular television tube, the beam current is 50.0 micro A. How long does it take for `4.75 * 10^14` electrons to strike the screen?

Answer 1

It takes `1.52"s"`.

Explanation:

The definition of Ampère is

`1"A"=1"C"/"s"`

we have `50\mu "A"=50*10^-6"C"/"s"`.

We have to know how many Coulombs of charge do we have in `4.75*10^14` electrons.

The charge of an electron is `1.6*10^(-19)"C"`, then our beam has

`4.75*10^14*1.6*10^(-19)"C"=7.6*10^-5"C"`.

The time to transport `7.6*10^-5"C"` in a current of `50\mu"A"` is then

`t=(7.6*10^-5"C")/(50*10^-6"C"/"s")=1.52"s"`.