Class 12 Alternating Current CBSE Questions & Answers

A 0.180-H inductor is connected in series with a 90.0 \(\Omega \) resistor and an ac source. The voltage across the inductor is (-12.0 V)sin(480 rad/s)t What is \({{\rm{V}}_{\rm{R}}}\) at t = 2ms ?

Domestic power supply in India is

In an L-R-C series circuit, the rms voltage across the resistor is 30.0 V, across the capacitor it is 90.0 V, and across the inductor it is 50.0 V. Rms voltage of the source is

An L-R-C series circuit has phase angle -31.5\(^\circ \).The voltage amplitude of the source is 90.0 V. Voltage amplitude across the resistor is

A series ac circuit contains a 250.0 \(\Omega \) resistor, a 15-mH inductor, a 3.5 \(\mu {\rm{F}}\) capacitor, and an ac power source of voltage amplitude 45 V operating at an angular frequency of 360 rad/s. Power factor of this circuit and the average power delivered to the entire circuit are

You have a 200.0 \(\Omega \) resistor, a 0.400-H inductor, a 5.0 \(\mu {\rm{F}}\) capacitor, and a variable frequency ac source with an amplitude of 3.00 V. You connect all four elements together to form a series circuit. Frequency at which current in the circuit is greatest and its amplitude are

You have a 200.0 \(\Omega \) resistor, a 0.400-H inductor, 5.0 \(\mu {\rm{F}}\) a capacitor, and a variable frequency ac source with an amplitude of 3.00 V. You connect all four elements together to form a series circuit. Current amplitude at an angular frequency of 400 rad/s is

A series circuit consists of an ac source of variable frequency, a 115.0 \(\Omega \) resistor, a 1.25 \(\mu {\rm{F}}\) capacitor, and a 4.50-mH inductor. Impedance of this circuit when the angular frequency of the ac source is adjusted to the resonant angular frequency is

A series circuit consists of an ac source of variable frequency, a 115.0 \(\Omega \) resistor, a 1.25 \(\mu {\rm{F}}\) capacitor, and a 4.50-mH inductor. Impedance of this circuit when the angular frequency of the ac source is adjusted to twice the resonant angular frequency is

A series circuit consists of an ac source of variable frequency, a 115.0 \(\Omega \) resistor, a 1.25 \(\mu {\rm{F}}\) capacitor, and a 4.50-mH inductor. Impedance of this circuit when the angular frequency of the ac source is adjusted to half the resonant angular frequency is

A coil has a resistance of 48.0 \(\Omega \). At a frequency of 80.0 Hz the voltage across the coil leads the current in it by 52.3\(^\circ \). Inductance of the coil is

A parallel-plate capacitor having square plates 4.50 cm on each side and 8.00 mm apart is placed in series with an ac source of angular frequency 650 rad/s and voltage amplitude 22.5 V, a 75.0 \(\Omega \) resistor, and an ideal solenoid that is 9.00 cm long, has a circular cross section 0.500 cm in diameter, and carries 125 coils per centimeter. What is the resonance angular frequency of this circuit?

A series circuit has an impedance of and a power factor of 0.720 at 50.0 Hz. The source voltage lags the current (a) What circuit element, an inductor or a capacitor, should be placed in series with the circuit to raise its power factor? (b) What size element will raise the power factor to unity?

In an LRC series circuit R = 300.0 \(\Omega \), XC = 300.0 \(\Omega \) and XL = 500.0 \(\Omega \). The average power consumed in the resistor is 60.0 W. (a) What is the power factor of the circuit?

In an LRC series circuit R = 300.0 \(\Omega \), XC = 300.0 \(\Omega \) and XL = 500.0 \(\Omega \). The average power consumed in the resistor is 60.0 W. rms voltage of the source is