MEDIUM
JEE Main
IMPORTANT
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In an LCR series circuit, an inductor 30 mH and a resistor 1 Ω are connected to an AC source of angular frequency 300 rad s-1. The value of capacitance for which the current leads the voltage by 45° is 1x×10-3 F. Then the value of x is

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Important Questions on Electromagnetic Induction and Alternating Currents

MEDIUM
JEE Main
IMPORTANT
For a series LCR circuit with R=100 Ω, L=0.5 mH and C=0.1 pF connected across 220 V-50 Hz AC supply, the phase angle between
current and supplied voltage and the nature of the circuit is:
MEDIUM
JEE Main
IMPORTANT
A series LCR circuit of R=5 Ω, L=20 mH and C=0.5 μF is connected across an AC supply of 250 V, having variable frequency. The power dissipated at resonance condition is ________×102 W.
EASY
JEE Main
IMPORTANT

In a circuit consisting of a capacitance and a generator with alternating emf, Eg=Egosinωt, VC and IC are the voltage and current. Correct phasor diagram for such circuit is

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MEDIUM
JEE Main
IMPORTANT

Match List-I with List-II.

  List - I   List - II
(a) ωL>1ωC (i) Current is in phase with emf
(b) ωL=1ωC (ii) Current lags behind the applied emf
(c) ωL<1ωC (iii) Maximum current occurs
(d) Resonant frequency (iv) Current leads the emf

Choose the correct answer from the options given below.

EASY
JEE Main
IMPORTANT
An inductor of 10 mH is connected to a 20 V battery through a resistor of 10  and a switch. After a long time, when maximum current is set up in the circuit, the current is switched off. The current in the circuit after 1 μs is x100 mA. Then x is equal to ______ . (Take e-1=0.37)
MEDIUM
JEE Main
IMPORTANT

A circular conducting coil of radius 1 m is being heated by the change of magnetic field B passing perpendicular to the plane in which the coil is laid. The resistance of the coil is 2 μΩ. The magnetic field is slowly switched off such that its magnitude changes in time as  

B=4π×10-3 T1-t100

The energy dissipated by the coil before the magnetic field is switched off completely is E=______mJ.

HARD
JEE Main
IMPORTANT
A 10 Ω resistance is connected across 220 V-50 Hz AC supply. The time taken by the current to change from its maximum value to the rms value is:
HARD
JEE Main
IMPORTANT

Two circuits are shown in figure (a) and (b). At a frequency of _______ rad s-1 the average power dissipated in one cycle will be the same in both the circuits.

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