Electro Magnetic Induction And Alternating Currents Question 9
Question: Same current is flowing in two alternating circuits. The first circuit contains only inductance and the other contains only a capacitor. If the frequency of the e.m.f. of ac is increased, the effect on the value of the current will be [MP PET 1993]
Options:
A) Increases in the first circuit and decreases in the other
B) Increases in both the circuits
C) Decreases in both the circuits
D) Decreases in the first circuit and increases in the other
Show Answer
Answer:
Correct Answer: D
Solution:
For the first circuit $ i=\frac{V}{Z}=\frac{V}{\sqrt{R^{2}+{{\omega }^{2}}L^{2}}} $
$ \therefore $ Increase in w will cause a decrease in i. For the second circuit $ i=\frac{V}{\sqrt{R^{2}+\frac{1}{{{\omega }^{2}}C^{2}}}} $
$ \therefore $ Increase in w will cause an increase in i.
