MEDIUM
NEET
IMPORTANT
Earn 100

The ac voltage is applied in circuits (a) (b) (c). If the frequency of emf is increased, what will be the effect upon current in these circuits?

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Important Questions on Alternating Current

MEDIUM
NEET
IMPORTANT
A bulb is connected in series with a variable capacitor. Will the bulb glow when this combination is connected to a DC supply/an AC supply? What would happen in each case, if the capacitance is reduced?
EASY
NEET
IMPORTANT
When a capacitor is connected in series with a series L-R circuit, the AC flowing in the circuit increases. Explain.
EASY
NEET
IMPORTANT
An AC circuit has a power factor of 0.5. What will be the phase difference between voltage and current in this circuit? Can you also tell whether the current leads the voltage or the voltage leads the current?
EASY
NEET
IMPORTANT

In the adjoining AC circuit, R is a pure resistance and X is an unknown circuit element. Using only an AC voltmeter how will you detect whether X is (i) pure inductance ?

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MEDIUM
NEET
IMPORTANT

what is the time lag between maximum current and main voltage?

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MEDIUM
NEET
IMPORTANT
How much current is drawn by the primary of a transformer which steps down 220 V to 22 V to operate a device having an impedance of 220 Ω?
MEDIUM
NEET
IMPORTANT
In an alternating-current circuit an inductance L, a capacitance C and a resistance R are connected in series. Derive expression for the impedance and the phase angle. What is the impedance at resonance?
HARD
NEET
IMPORTANT
Explain the principle, construction and working of a choke coil in controlling current in an AC circuit. Why is it preferred to resistance in AC circuits?