Chapter 7: Alternating Current MCQs | physics Class 12 CBSE

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Question 1

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In a pure resistor connected to an ac source, the phase difference between voltage and current is:

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Question 2

Objective

The rms value of an alternating current with peak value im is:

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Question 3

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The household supply voltage is 220 V (rms). Its peak voltage is approximately:

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Question 4

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Average power dissipated per cycle in a pure inductor connected to ac source is:

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Question 5

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Inductive reactance of a coil is XL at frequency f. At frequency 2f, the inductive reactance will be:

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Question 6

Objective

In a pure capacitor connected to ac source, current:

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Question 7

Objective

Capacitive reactance XC = 1/(ωC). If the frequency of the ac source is doubled, XC becomes:

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Question 8

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The impedance of a series LCR circuit is given by:

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Question 9

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At resonance in a series LCR circuit, the impedance equals:

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Question 10

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The resonant angular frequency of a series LCR circuit is:

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Question 11

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The power factor of an ac circuit is defined as:

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Question 12

Objective

In a purely capacitive ac circuit, the power factor is:

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Question 13

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A phasor is a vector that rotates about the origin with angular speed ω. The vertical component of the phasor represents:

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Question 14

Objective

For a series LCR circuit with XC > XL, the nature of the circuit is:

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Question 15

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The average power in an ac circuit is P = VI cos φ. For maximum power, the phase angle φ should be:

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Question 16

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The voltage transformation ratio of a transformer is Vs/Vp = Ns/Np. For a step-up transformer:

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Question 17

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In a transformer, eddy current losses in the iron core are minimized by:

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Question 18

Objective

A 44 mH inductor is connected to 220 V, 50 Hz ac supply. The inductive reactance is approximately:

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Question 19

Objective

Which of the following correctly states the condition under which resonance CANNOT occur?

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Question 20

Objective

In an LCR series circuit at resonance, the voltages across L and C are found to be 200 V each, and the source voltage is 100 V. Which statement is correct?

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Chapter 7: Alternating Current | MCQs

In a pure resistor connected to an ac source, the phase difference between voltage and current is:

The rms value of an alternating current with peak value im is:

The household supply voltage is 220 V (rms). Its peak voltage is approximately:

Average power dissipated per cycle in a pure inductor connected to ac source is:

Inductive reactance of a coil is XL at frequency f. At frequency 2f, the inductive reactance will be:

In a pure capacitor connected to ac source, current:

Capacitive reactance XC = 1/(ωC). If the frequency of the ac source is doubled, XC becomes:

The impedance of a series LCR circuit is given by:

At resonance in a series LCR circuit, the impedance equals:

The resonant angular frequency of a series LCR circuit is:

The power factor of an ac circuit is defined as:

In a purely capacitive ac circuit, the power factor is:

A phasor is a vector that rotates about the origin with angular speed ω. The vertical component of the phasor represents:

For a series LCR circuit with XC > XL, the nature of the circuit is:

The average power in an ac circuit is P = VI cos φ. For maximum power, the phase angle φ should be:

The voltage transformation ratio of a transformer is Vs/Vp = Ns/Np. For a step-up transformer:

In a transformer, eddy current losses in the iron core are minimized by:

A 44 mH inductor is connected to 220 V, 50 Hz ac supply. The inductive reactance is approximately:

Which of the following correctly states the condition under which resonance CANNOT occur?

In an LCR series circuit at resonance, the voltages across L and C are found to be 200 V each, and the source voltage is 100 V. Which statement is correct?

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