Question

In a hydrogen discharged tube it is observed that through a given cross-section $3.13\times {10}^{15}$ electrons are moving from right to left and $3.12\times {10}^{15}$ protons are moving from left to right. What is the electric current in the discharge tube and what is its direction?

• A. $1mA$ towards right
• B. $1mA$ towards left
• C. $2mA$ towards left
• D. $2mA$ towards right

Answer 1

The correct option is A $1mA$ towards right

The direction of flow of current is opposite to the direction of the electron.

The direction of flow of current is same as the the direction of flow of proton.

$I=n_e{q}_e+n_p{q}_E$

$I=3.13\times {10}^{15}\times 1.6\times {10}^{-19}+3.12\times {10}^{15}\times 1.6\times {10}^{-19}$

=1mA(towards right)