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

Hint:

The current due to electrons is opposite to the direction of flow of the charge, but the current direction follows the conventional flow.

Answer 1

The Correct Option is A

The electric current is the rate of flow of charge. Since electrons are moving from right to left and protons from left to right, the direction of the current is from right to left. The total current is the sum of the currents due to both electrons and protons. The current is 1 mA in the rightward direction.

Step 2: Conclusion.
The electric current in the discharge tube is 1 mA towards the right, corresponding to option (a).