A step-up transformer operates on a 230 V line and supplies a current of 2 A. The ratio of primary and secondary winding is 1:25. The primary current is
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(a) 12.5 A […]
Transformer is used to
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(a) convert AC to DC voltage (b) convert DC to AC voltage (c) obtain desired DC power (d) obtain desired AC voltage and current
Correct Answer:
obtain desired […]
The average power dissipated in a pure inductor is
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(a) VI²/4 (b) 1/2 VI (c) zero (d) VI²
Correct Answer:
zero
Explanation:
In the inductor circuit, phase difference (ɸ) = 90° or π […]
In a circuit, L,C and R are connected in series with an alternating voltage source of frequency f. The current leads the voltage by 45⁰. The value of C is
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(a) 1/πf(2πfL+R) (b) […]
In an L-C-R series resonant circuit, the capacitance is changed from C to 4C. For the same resonant frequency, the inductance should be changed from L to
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(a) 2L (b) L/2 (c) 4L […]
The electric current in AC circuit is given by the relation i-3 sinωt+4 cosωt. The rms value of the current in the circuit in ampere is
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(a) 5/√2 (b) 5√2 (c) √2/5 (d) […]
In a circuit, the current lags behind the voltage by a phase difference of π/2. The circuit contains which of the following?
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(a) Only L (b) Only C (c) Only R (d) […]
An inductor coil is connected to a 12 V battery and drawing a current 24 A. This coil is connected to capacitor and an AC source of rms voltage rating 24 V in the series […]
An alternating voltage given as, V=100√2 sin100t V is applied to a capacitor of 1 μF. The current reading of the ammeter will be equal to …….. mA
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(a) 20 (b) 10 (c) […]
An inductor 20 mH, a capacitor 50 μF and a resistor 40Ω are connected in series across a source of emf V=10 sin340t. The power loss in AC circuit is
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(a) 0.67 […]
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