Beta Question Bank for Engineering: Physics>Chapter 28 - Alternating Current>Exercise-1>Q 10

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IMPORTANT

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A student connects a long air-cored coil of manganin wire to a $100 V$ DC supply and records a current of $25 A$ . When the same coil is connected across $100 V, 50 Hz$ AC, the current reduces to $20 A$ . The reactance of the coil is

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Important Questions on Alternating Current

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IMPORTANT

Beta Question Bank for Engineering: Physics>Chapter 28 - Alternating Current>Exercise-1>Q 11

If value of $R$ is changed, then

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Beta Question Bank for Engineering: Physics>Chapter 28 - Alternating Current>Exercise-1>Q 12

In a circuit

L, C

and

R

are connected in series with an alternating voltage source of frequency

f

. The current leads the voltage by

45 ° .

The value of

C

is

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Beta Question Bank for Engineering: Physics>Chapter 28 - Alternating Current>Exercise-1>Q 13

In an LCR series AC circuit, the voltage across each of the components

L

,

C

and

R

is

50 V

. The voltage across the LC combination will be?

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Beta Question Bank for Engineering: Physics>Chapter 28 - Alternating Current>Exercise-1>Q 14

In an

L - C - R

circuit capacitance is changed from

C

to

2 C

. For the resonant frequency to remain unchanged, the inductance should be changed from

L

to

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IMPORTANT

Beta Question Bank for Engineering: Physics>Chapter 28 - Alternating Current>Exercise-1>Q 15

In a series resonance LCR circuit, the voltage across

R

is

100 V

and

R

is

1 kΩ

with

C = 2 μF

. The resonant frequency

ω

is

200 rad s^{- 1}

. At resonance, the voltage across

L

is

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Beta Question Bank for Engineering: Physics>Chapter 28 - Alternating Current>Exercise-1>Q 16

In the adjoining $AC ckt$ . the voltmeter whose reading will be zero at resonance is

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Beta Question Bank for Engineering: Physics>Chapter 28 - Alternating Current>Exercise-1>Q 17

In $LCR$ circuit, the voltage across the terminals of a resistance and current will be

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Beta Question Bank for Engineering: Physics>Chapter 28 - Alternating Current>Exercise-1>Q 18

An ac source of angular frequency

ω

is fed across a resistor

R

and a capacitor

C

in series. The current registered is

I

. If now, the frequency of the source is changed to

\frac{ω}{3}

(but maintaining the same voltage), the current in the circuit is found to be halved. Calculate the ratio of reactance to resistance at the original frequency

ω

.