Impedance

Trending Questions

Q. A series R-C circuit is connected to an alternating voltage source. Consider two situations:
(a) When capacitor is filled with air
(b) When capacitor is filled with mica
Current through resistor is

i

and voltage across capacitor is

V_{a}

in case (a) and

V_{b}

in case (b), then

$V_{a} = V_{b}$
$V_{a} < V_{b}$
$V_{a} > V_{b}$
$i_{a} = i_{b}$

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Q. An alternating current of frequency 'f' is flowing in a circuit containing a resistance R and a choke L in series. The impedance of this circuit is

$R + 2 π f L$
$\sqrt{R^{2} + 4 π^{2} f^{2} L^{2}}$
$\sqrt{R^{2} + L^{2}}$
$\sqrt{R^{2} + 2 π f L}$

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Q. A coil of resistance

300 Ω

and inductance

1.0 H

is connected across an alternating voltage of peak value

300 V

of frequency

\frac{300}{2 π} H z .

Calculate the peak potential difference across inductor.

$150 \sqrt{2} V$
$150 V$
$100 \sqrt{2} V$
$100 V$

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Q. When a

100 V DC

is applied across a solenoid, a current of 1.0 A flows in it. When a

100 V AC

is applied across the same coil, the current drops to

0.5 A

. If the frequency of the

A C

source is

50 Hz

, the impedance and inductance of the solenoid are

$200 Ω$ and $0.55 H$
$100 Ω$ and $0.86 H$
$200 Ω$ and $1.0 H$
$100 Ω$ and $0.93 H$

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