MEDIUM
JEE Main
IMPORTANT
Earn 100

Remove the inductor from the circuit in the figure and set R=400 Ω, C=15.0 μF, fd=30.0 Hz, and Em=72.0 V. What are
(a) Z, (b) ϕ,and
(c) I ?
(d) Draw a phasor diagram.

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Important Questions on Electromagnetic Oscillations and Alternating Current

HARD
JEE Main
IMPORTANT

Figure shows a driven RLC circuit that contains two identical capacitors and two switches. The emf amplitude is set at 12.0 V, and the driving frequency is set at 60.0 Hz. With both switches open, the current leads the emf by 25.0°. With switch S1, closed and switch S2 still open, the emf leads the current by 20.0° . With both switches closed, the current amplitude is 447 mA . What are (a) R,(b) C, and (c) L? Take tan20°=0.364 and tan25°=0.466

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EASY
JEE Main
IMPORTANT
In an oscillating LC circuit, L=5.97 mH and C=4.00 μF. The maximum charge on the capacitor is  3.00 μC. Find (a) the maximum current and (b) the oscillation period. 
EASY
JEE Main
IMPORTANT
To construct an oscillating LC system, you can choose from 10 mH a inductor, a 8.0 μF capacitor, and a 4.0 μF capacitor. What are the (a) smallest,
(b) second smallest, (c) second largest, and
(d) largest oscillation frequency that can be set up by these elements in various combinations?
HARD
JEE Main
IMPORTANT

In RLC an circuit, assume that R=12.0 ΩL=60.0 mH, fd=60.0 Hz, and  εm=30.0 V. For what values of the
capacitance would the average rate at which energy is dissipated in the resistance be (a) a maximum and (b) a minimum? What are
(c) the maximum dissipation rate and the corresponding
(d) phase angle and (e) power factor? What are (f) the minimum dissipation rate and the corresponding
(g) phase angle and (h) power factor?

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HARD
JEE Main
IMPORTANT

An alternating emf source with a variable frequency fd is connected in series with a 50.0 Ω resistor and a 28.0 μF capacitor. The emf amplitude is 12.0 V .

(a) Draw a phasor diagram for VR phasor (the potential across the resistor) and phasor VC (the potential across the capacitor).

(b) At what driving frequency fd do the two phasors have the same length?

At that driving frequency, what are
(c) the phasor angle in degrees,

(d) the angular speed at which the phasors rotate, and

(e) the current amplitude?

HARD
JEE Main
IMPORTANT
In an oscillating series RLC  circuit, show that ΔU/U  , the fraction of the energy lost per cycle of oscillation, is given to a close approximation by 2πR/ωL. The quantity ωL/R  is often called the Q of the circuit (for quality). A high-Q circuit has low resistance and a low fractional energy loss (=2π/Q) per cycle.
MEDIUM
JEE Main
IMPORTANT
In an oscillating LC circuit in which C=6.00 μF , the maximum potential difference across the capacitor during the oscillations is 1.50 V and the maximum current through the inductor is 50.0 mA. What are a the inductance L and b the frequency of the oscillations? c How much time is required for the charge on the capacitor to rise from zero to its maximum value?
MEDIUM
JEE Main
IMPORTANT

 A 85.0 mH inductor is connected as in the figure, to an AC generator with Em=30.0 V. What is the amplitude of the resulting alternating current if the frequency of the emf is
a 1.00 kHz and b 5.00 kHz?

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