Current Electricity Charging Discharging Of Capacitors Question 125
Question: The wiring of a house has resistance $ 6,\Omega . $ A 100 W bulb is glowing. If a geyser of 1000 W is switched on, the change in potential drop across the bulb is nearly
[MNR 1998]
Options:
A) Nil
B) 23 V
C) 32 V
D) 12 V
Show Answer
Answer:
Correct Answer: B
Solution:
$ R _{Bulb}=\frac{220^{2}}{100}=484\Omega $ , $ R _{Geyser}=\frac{220^{2}}{1000}=48.4\Omega $ (i) When only bulb is ON, $ V _{Bulb}=\frac{220\times 484}{490}=217.4,V $ (ii) When geyser is also switched ON, equivalent resistance of bulb and geyser is $ R=\frac{484\times 48.4}{484+48.4}=44,\Omega $ Voltage across the bulb $ V _{Bulb}=\frac{220\times 44}{50}=193.6,V $ Hence the potential drop is $ 217.4-193.6=23.8V $
BETA
