Question

In a hydrogen discharge tube, if $n_1$ and $n_2$ be the number of electrons and protons passing per second, through a given cross section of the tube, the current in the distance tube is

• A. $(n_1-n_2)e$ in the direction of electron flow
• B. $(n_1+n_2)e$ in the opposite direction of electron flow
• C. $\frac{(n_1+n_2)}{e}$ in the direction of electron flow
  
• D. $\frac{(n_1+n_2)}{e}$ in the opposite direction of electron flow
  

Answer 1

The correct option is B $(n_1+n_2)e$ in the opposite direction of electron flow

The total number of charge particles flow though cross-section of tube per second $n=n_1+n_2$

So net charge flow per sec is the current i.e, $I=ne=(n_1+n_2)e$

The current is always flow opposite to the flow of electrons.