Physics Quiz 1 Chapter 7
Alternating Current
NAME OF STUDENT *
CLASS *
MOBILE NO. *
Q .1 An electrical element X when connected to an alternating voltage source has current through it leading the voltage by π/2 radian. Identify X *
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Q. 2 Average power dissipated in an ideal inductor in a.c. circuit is: *
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Q. 3 A Capacitor blocks *
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Q.4 A transformer steps up 220 V to2200 V. What is the transformation ratio? *
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Q.5 In which of the following circuits the maximum power dissipation is observed? *
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Q.6 The instantaneous current in an ac circuit is i=2.0 sin314t, what is its frequency? *
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Q.7 The instantaneous current in an ac circuit is i=2.0 sin314t, what is rms value of the current *
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Q.8 An L,C, R series circuit is connected to a.c. source. At resonance, the applied voltage and the current flowing through the circuit will have a phase difference of *
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Q.9 In an a.c. circuit, containing an inductance and a capacitor in series, the current is found to be maximum when the value of inductance is 0.5henry and of capacitance is 8μF. The angular frequency of the input A.C. Voltage must be equal to *
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Q.10 In a transformer, number of turns in the primary are 140 and that in the secondary are 280. If current in primary is 4A, then that in the secondary is *
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Q.11 In a series LCR circuit, resistance R = 10 and the impedance Z = 20. The phase difference between the current and the voltage is *
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Q.12 In the case of an inductor : *
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Q.13 In an AC circuit, V and I are given by V=150 sin (150t) volts and I = 150 sin (150t) amperes. The power dissipated in the circuit is: *
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Q. 14 An A.C source is connected to a resistive circuit. Which of the following is true ? *
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Q.15 The output voltage of an ideal transformer, connected to a 240V a.c. mains is 24V. When this transformer is used to light a bulb with rating (24V, 24W), calculate the current in the primary coil of the circuit. *
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Q. 16 In an LCR-series ac circuit, the voltage across each of the component L, C and R is 50 V. The voltage across the LC-combination will be *
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Q. 17 The core of any transformer is laminated so as to. *
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Q. 18 For an ideal-step-down transformer, the quantity which is constant for both the coils is. *
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Q.19 To reduce the resonant frequency in an LCR series circuit with a generator . *
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Q. 20 When an AC voltage of 220 V is applied to the capacitor C . *
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