Question

In a particular television tube, a beam of electrons is emitted. The beam curren is 80 micro ampere. How many electrons strike the screen of TV every second? Also find the total charge striking the screen in two minutes.

Answer 1

I = q/t
q = ne

for no. electron per sec
ne = I = 80 × 10^-6
n = 80 x 10^-6 ÷(1.6x10^-19)
= 50x10^13 no. of electron strike the screen per second

in two minute
q = It
= 120x80x10^-6
= 9.6x10^-3 coulomb

Answer 2

Given:

We have the beam curren is 80 micro ampere.

To Find:

We need to find no. of  electrons strike the screen of TV every second? Also find the total charge striking the screen in two minutes.

Explanation:

• Let I be represent the current and Q be charge and T is time

• We know Charge can be written as product of current and time

          $80{\textrm{micro ampere}=80\times10^-^6$

• Now number of electron striking every second can be calculated by

          $n=\frac{I}{e} \\n=\frac{80\times10^-^6}{1.6\times10^-^9}=50\times10^3$

• Hence, number of electron striking per second will be above.

• Now charge striking the screen cal be calculate by

              $Q=TI\\Q=120\times80\times10^-^6\\Q=9.6\times10^-^3$