﻿ AC - Alternating Current Set 1, NCERT Physics Class 12 - MCQ Quiz by Dr. Mukesh Shrimali

# Topic AC - Alternating Current Set 1, Physics MCQ Quiz Test

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MCQ 1:
In an A.C. circuit capacitance of 5μF has a reactance as 1/1000 Ω. The frequency of A.C. in MHz will be -

MCQ 2:
In an A.C. circuit XL = 300Ω, XC = 200Ω and R = 100Ω the impedance of circuit is -

MCQ 3:
A resistance of 50Ω, an inductance of 20/π Henry and a capacitor of 5/π μF are connected in series with an A.C. source of 230 volt and 50 Hz. The impedance of circuit is -

MCQ 4:
In an L–C–R series circuit R = √5 Ω, XL = 9Ω and XC = 7Ω. If applied voltage in the circuit is 50 volt then impedance of the circuit in ohm then impedance of the circuit in ohm will be -

MCQ 5:
The potential difference between the ends of a resistance R is VR between the ends of capacitor is VC = 2VR and between the ends of inductance is VL = 3VR, then the alternating potential of the source in terms of VR will be -

MCQ 6:
In an A.C. circuit the impedance is Z = 100 ∠30° Ω, then the resistance of the circuit in ohm will be -

MCQ 7:
In an LCR circuit, the voltages across the components are VL, VC and VR respectively. The voltage of source will be -

MCQ 8:
In an electric circuit the applied alternating emf is given by E = 100 sin (314 t) volt, and current flowing I = sin (314t + π/3). Then the impedance of the circuit is (in ohm) -

MCQ 9:
The percentage increase in the impedance of an ac circuit, when its power factor changes form 0.866 to 0.5 is (Resistance constant) -

MCQ 10:
The impedance of the given circuit will be -

MCQ 11:
The impedance of the given circuit will be -

MCQ 12:
If E0 = 200 volt, R = 25 ohm, L = 0.1 H and C = 10-5 F and the frequency is variable, then the current at f = 0 and f = ∞ will be respectively -

MCQ 13:
The impedance of the circuit given will be -

MCQ 14:
A coil of resistance R and inductance L is connected to a cell of emf E volt. The current flowing through the coil will be -

MCQ 15:
In a certain circuit E = 200 cos (314t) and I = sin (314t + π/4). Their vector representation is -

MCQ 16:
In a certain circuit E = 200 cos (314t) and I = sin (314t + π/4), the reactance X will be -

MCQ 17:
In a certain circuit E = 200 cos (314t) and I = sin (314t + π/4), the power factor is -

MCQ 18:
The electric resonance is sharp in L-C-R circuit if in the circuit -

MCQ 19:
In a series resonant L–C–R circuit, if L is increased by 25% and C is decreased by 20%, then the resonant frequency will -

MCQ 20:
If R = 100 Ω then the value of X and I in the given circuit will be -

MCQ 21:
If R = 100 Ω, the value of inductance will be -

MCQ 22:
In an LCR. series circuit the resonating frequency can be decreased by -

MCQ 23:
Which of the following statements is correct for L–C–R series combination in the condition of resonance -

MCQ 24:
In an LCR circuit, the resonating frequency is 500 kHz. If the value of L is increased two times and value of C is decreased 1/8 times, then the new resonating frequency in kHz will be -

MCQ 25:
In resonating circuit value of inductance and capacitance is 0.1H and 200 μF. For same resonating frequency if value of inductance is 100H then necessary value of capacitance in μF will be -

MCQ 26:
The inductance of the motor of a fan is 1.0 H. To run the fan at 50 Hz the capacitance of the capacitor that will cancel its inductive reactance, will be -

MCQ 27:
In ac circuit at resonance -

MCQ 28:
An ac circuit resonates at a frequency of 10 kHz. If its frequency is increased to 11 kHz, then -

MCQ 29:
?n an ac circuit 6 ohm resistor, an inductor of 4 ohm and a capacitor of 12 ohm are connected n series with an ac source of 100 volt (rms). The average power dissipated in the circuit will be -

MCQ 30:
In an ac circuit emf and current are E = 5 cos ωt volt and I = 2 sin ωt ampere respectively. The average power dissipated in this circuit will be -

MCQ 31:
The equations of alternating e.m.f. and current in an A.C. circuit are E = 5 cos ωt volt and I = 2 sin (ωt + π/6) ampere respectively. The average power loss in this circuit will be -

MCQ 32:
The series combination of resistance R and inductance L is connected to an alternating source of e.m.f. e = 311 sin (100 πt). If the value of wattless current is 0.5A and the impedance of the circuit is 311?????, the power factor will be -

MCQ 33:
In an L–C–R series circuit the loss of power is in -

MCQ 34:
In an ac circuit the readings of an ammeter and a voltmeter are 10 A and 25 volt respectively, the power in the circuit will be -

MCQ 35:
A choke coil of 100 ohm and 1 H is connected to a generator of E = 200 sin (100t) volt. The average power dissipated will be -

MCQ 36:
A choke coil of negligible resistance carries 5 mA current when it is operated at 220 V. The loss of power in the choke coil is -

MCQ 37:
The ratio of apparent power and average power in an A.C. circuit is equal to –

MCQ 38:
In an A.C. circuit, a resistance of 3 Ω, an inductance coil of 4 Ω and a condenser of 8 Ω are connected in series with an A.C. source of 50 volt (R.M.S.). The average power loss in the circuit will be -

MCQ 39:
In an A.C. circuit, i = 5 sin (100t – π/2) ampere an A,V, V = 200 sin (100 t) volt. The power loss in the circuit will be -

MCQ 40:
When N identical bulbs are connected in parallel, total power consumption is P, what would be the power consumption when they connected in series-

MCQ 41:
Two bulbs of 500 watt and 300 watt work on 200 volt r.m.s. the ratio of their resistances will be -

MCQ 42:
An air core coil and an electric bulb are connected in series with an A.C. source. If an iron rod is put in the coil, then the intensity of bulb's will-

MCQ 43:
If a bulb and a coil are connected in series with D.C. source and a iron core put in the coil then the glowing of bulb -

MCQ 44:
Three bulbs of 40, 60 and 100 watt are connected in series with the source of 200 volt. Then which of the bulb will be glowing the most -

MCQ 45:
If two bulbs each of 220V, 30 watt are connected in series, then we get electric power as -

MCQ 46:
Two electric bulbs of 100 watt (220 volt) are connected in series and these are connected with other bulb of 100W (220V) in parallel then total power in watt will be -

MCQ 47:
The A.C. meters are based on the principle of -

MCQ 48:
The correctly marked ammeter for A.C. current is shown in -

MCQ 49:
Alternating current can not be measured by direct current meters, because -

MCQ 50:
The A.C. meters measure its -