Question

In a helium discharge tube every second 40×10^18He+( ions ) move towards the right through a cross-section of the tube, while n electrons move to the left in the same time. If the current in the tube is 8 A towards right then the value of n is​
1)3×10^18
2)3×10^19
3)3×10^20
4)3×10^21​

Answer 1

Answer:

Net current=current due to He

+

+ current elements

⇒8Amp=

1sec

40×10

18

×1.6×10

−19

+

1sec

n×1.6×10

−19

⇒

1.6×10

−19

8

=n+40×10

18

but n+40×10

18

=50×10

18

so, n=10×10

18

=10

19

.

solution