Current Electricity Charging Discharging Of Capacitors Question 516

Question: A bulb rated at (100W ? 200V) is used on a 100V line. The current in the bulb is

[JIPMER 1999]

Options:

A) $ \frac{1}{4} $ amp

B) 4 amp

C) $ \frac{1}{2} $ amp

D) 2 amp

Show Answer

Answer:

Correct Answer: A

Solution:

$ P=\frac{V^{2}}{R}\Rightarrow 100=\frac{{{(200)}^{2}}}{R} $

Therefore $ R=\frac{4\times 10^{4}}{10^{2}}=400,\Omega $ Now, $ i=\frac{V}{R}=\frac{100}{400}=\frac{1}{4}amp $