Same current is flowing in two alternating circuits. The first ci… - Vidyadip

MCQ

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

A
Increases in the first circuit and decreases in the other
B
Increases in both the circuits
C
Decreases in both the circuits
✓
Decreases in the first circuit and increases in the other

✓

Answer

Correct option: D.

Decreases in the first circuit and increases in the other

d
(d) For the first circuit $i = \frac{V}{Z} = \frac{V}{{\sqrt {{R^2} + {\omega ^2}{L^2}} }}$
$\therefore $ Increase in $\omega$ 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 will cause an increase in i.

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