Class 12 Physics - Chapter 7: Alternating Current MCQ Questions

10 Questions 20 Minutes

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Your Class 12 Physics Study Path

Question 1

If the rms current in a 50 Hz ac circuit is 5 A, the value of the current 1/300 second after its value becomes zero is

A 5/âˆš2 A

B 5/6 A

C 5âˆš3 /2 A

D 5âˆš2A

Question 2

As the frequency of an ac circuit increases, the current first increases and then decreases. What combination of circuit elements is most likely to comprise the circuit?

A None.

B Resistor and capacitor.

C Resistor and inductor.

D Inductor and capacitor.

Question 3

In an ac circuit, V and i are given by V = 100 sin (100 t) volt and i = 100 sin (100 + (frac { Ï€ }{3})) mA. The power dissipated in circuit is

A 5 W

B 2.5 W

C 10 W

D 104 W

Question 4

The potential differences across the resistor, capacitor and inductor are 80 V, 40 V and 100 V, respectively in an LCR circuit. The power factor of this circuit is:

A 0.5

B 0.4

C 1.0

D 0.8

Question 5

To reduce the resonant frequency in an LCR series circuit with a generator

A dielectric in the capacitor should be removed.

B the iron core of the inductor should be removed.

C another capacitor should be added in parallel to the first.

D the generator frequency should be reduced.

Question 6

In an alternating current circuit consisting of elements in series, the current increases on increasing the frequency of supply. Which of the following elements are likely to constitute the circuit?

A Only a capacitor.

B Capacitor and an inductor.

C Resistor and an inductor.

D Only resistor.

Question 7

A small signal voltage V(t) = V₀ sinÏ‰ t is applied across an ideal capacitor C

A Current l(t) leads voltage V(t) by 180Â°.

B Current l(t) is in phase with voltage V(t).

C Over a full cycle the capacitor C does not consume any energy from the voltage source.

D Current l (t) lags voltage V(t) by 90Â°.

Question 8

When an AC voltage of 220 V is applied to the capacitor C

A power delivered to the capacitor is zero.

B the charge on the plates is out of phase with the applied voltage.

C the current is in phase with the applied voltage.

D the maximum voltage between plates is 220 V.

Question 9

Electrical energy is transmitted over large distances at high alternating voltages. Which of the following statements is incorrect?

A It is easy to reduce the voltage at the receiving end using step-down transformers.

B Transmission lines can be made thinner.

C Lower current implies less power loss.

D For a given power level, there is a lower current.

Question 10

The output of a step-down transformer is measured to be 24 V when connected to a 12 watt light bulb. The value of the peak current is

A 2âˆšV2A

B 2A

C âˆš2A

D 1/âˆš2A

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Class 12 Physics - Chapter 7: Alternating Current MCQ Questions

Your Class 12 Physics Study Path

If the rms current in a 50 Hz ac circuit is 5 A, the value of the current 1/300 second after its value becomes zero is

As the frequency of an ac circuit increases, the current first increases and then decreases. What combination of circuit elements is most likely to comprise the circuit?

In an ac circuit, V and i are given by V = 100 sin (100 t) volt and i = 100 sin (100 + (frac { Ï€ }{3})) mA. The power dissipated in circuit is

The potential differences across the resistor, capacitor and inductor are 80 V, 40 V and 100 V, respectively in an LCR circuit. The power factor of this circuit is:

To reduce the resonant frequency in an LCR series circuit with a generator

In an alternating current circuit consisting of elements in series, the current increases on increasing the frequency of supply. Which of the following elements are likely to constitute the circuit?

A small signal voltage V(t) = V₀ sinÏ‰ t is applied across an ideal capacitor C

When an AC voltage of 220 V is applied to the capacitor C

Electrical energy is transmitted over large distances at high alternating voltages. Which of the following statements is incorrect?

The output of a step-down transformer is measured to be 24 V when connected to a 12 watt light bulb. The value of the peak current is

Practice Complete!

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Class 12 Physics - Chapter 7: Alternating Current MCQ Questions

Your Class 12 Physics Study Path

If the rms current in a 50 Hz ac circuit is 5 A, the value of the current 1/300 second after its value becomes zero is

As the frequency of an ac circuit increases, the current first increases and then decreases. What combination of circuit elements is most likely to comprise the circuit?

In an ac circuit, V and i are given by V = 100 sin (100 t) volt and i = 100 sin (100 + (frac { Ï€ }{3})) mA. The power dissipated in circuit is

The potential differences across the resistor, capacitor and inductor are 80 V, 40 V and 100 V, respectively in an LCR circuit. The power factor of this circuit is:

To reduce the resonant frequency in an LCR series circuit with a generator

In an alternating current circuit consisting of elements in series, the current increases on increasing the frequency of supply. Which of the following elements are likely to constitute the circuit?

A small signal voltage V(t) = V0 sinÏ‰ t is applied across an ideal capacitor C

When an AC voltage of 220 V is applied to the capacitor C

Electrical energy is transmitted over large distances at high alternating voltages. Which of the following statements is incorrect?

The output of a step-down transformer is measured to be 24 V when connected to a 12 watt light bulb. The value of the peak current is

Practice Complete!

Related Student Tools

Grade Calculator

Marks Percentage Calculator

Percentage Calculator

Students Also Read

Discover More on SaralStudy

Latest Blogs

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Quick Links

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What Students Are Viewing

A small signal voltage V(t) = V₀ sinÏ‰ t is applied across an ideal capacitor C