Current Electricity Charging Discharging Of Capacitors Question 538
Question: If a 30 V, 90 W bulb is to be worked on a 120 V line, a resistance of how many ohms should be connected in series with the bulb
[MP PMT 2002; KCET 2003]
Options:
A) 10 ohm
B) 20 ohm
C) 30 ohm
D) 40 ohm
Show Answer
Answer:
Correct Answer: C
Solution:
Suppose resistance R is corrected in series with bulb. Current through the bulb $ i=\frac{90}{30}=3,A $ Hence for resistance $ V=i,R $
Therefore $ 90=3\times R\Rightarrow R=30,\Omega $
BETA
