In hydrogen discharge tube, it is observed that through a given cross-section 3.13 × 10 15 electrons are moving from right to left and 3.12 × 10 15 protons are moving from left to right per second. The current in the discharge tube (in mA ) will be

Step-by-step solution

Number of electrons n e = 3.13 × 10 15 Number of protons n p = 3.12 × 10 15 Now, the current is given by the relation i = n e q e + n p q p = 3.13 × 10 15 × 1.6 × 10 - 19 + 3.12 × 10 15 × 1.6 × 10 - 19 = 1 × 10 - 3 = 1   mA Now, due to excess the charge on electrons, the direction of the current will be towards the right.