Question

In a discharge tube when $200volt$ potential difference is applied $6.25\times {10}^{18}$ electron move from cathode to anode and $3.125\times {10}^{18}$ singly charged positive ion move from anode to cathode in one second. Then the power of tube is:

• A. $100watt$
• B. $200watt$
• C. $300watt$
• D. $400watt$

Answer 1

The correct option is C $300watt$

Potential difference, V=200V

Current, $I=\frac{Q}{t}=n_e\times e+n_p\times e(t=1s)=(6.25\times {10}^{18}\times 1.6\times {10}^{-19})=1+0.5=1.5Power,P=VI=200\times 1.5=300W$