Neet Solved Paper 2013 Question 32
Question: A coil of self-inductance L is connected in series with a bulb -B and an AC source. Brightness of the bulb decreases when
Options:
A) frequency of the AC source is decreased
B) number of turns in the coil is reduced
C) a capacitance of reactance $ X _{C}=X _{L} $ is included in the same circuit
D) an iron rod is inserted in the coil
Show Answer
Answer:
Correct Answer: D
Solution:
- As $ Z=\sqrt{R^{2}+X_L^{2}}=\sqrt{R^{2}+{{(2\pi fvL)}^{2}}} $ As $ l=\frac{V}{Z},p=l^{2}R $ i.e., $ V\uparrow ,L\uparrow \Rightarrow Z\uparrow ,l\downarrow $ and $ P\downarrow $
