Alternating Current - NEET Physics Questions
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Alternating Current

Question 11: moderate

In a purely inductive AC circuit, which of the following sketches represent the variation of the current amplitude I0 with the frequency ω ?

1.
2.
3.
4.
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Question 12: moderate

The phase difference between applied voltage and current in RLC series is :

1. Positive when \[X_{L}\gt X_{C} \]
2. Positive when \[X_{C}\gt X_{L} \]
3. 90°
4.
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Question 13: moderate

Consider following in AC circuits and their characteristics :

1. P - 1, Q - 2, R - 3, S - 4
2. P - 1, Q - 4, R - 2, S - 3
3. P - 4, Q - 2, R - 1, S - 3
4. P - 3, Q - 4, R - 2, S - 1
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Question 14: moderate

A fully charged capacitor C, with initial charge q0, is connected to a coil of self inductance L at t = 0. The time at which the energy is stored equally between the electric and magnetic field is:

1. \[2\pi\sqrt{LC}\]
2. \[\sqrt{LC}\]
3. \[\pi\sqrt{LC}\]
4. \[\frac{\pi}{4}\sqrt{LC}\]
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Question 15: difficult

The graph shows variation of I with f for a series R-L-C network. Keeping L and C constant. If R
decreases :

(a) Maximum current (Im) increases
(b) Sharpness of the graph increases
(c) Quality factor increases
(d) Band width increases

1. a, b, c
2. b, c, d
3. c, d, a
4. All
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Question 16: moderate

In an a.c. circuit V and I are given by
V = 100 sin (100 t) volts
I = 100 sin (100t + π/3) mA
The power dissipated in the circuit is

1. \[10^{4} watt\]
2. 10 watt
3. 2.5 watt
4. 5.0 watt
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Question 17: moderate

A condenser of capacity C is charged to a potential difference of V1. The plates of the condenser are then connected to an ideal inductor of inductance L.  The current through the indictors when the potential difference across the condenser reduces to V2 is ?

1. \[\frac{C\left( V_{1}^{2}-V_{2}^{2} \right)}{2}\]
2. \[\frac{C\left( V_{1}^{2}+V_{2}^{2} \right)}{2}\]
3. \[\left( \frac{C\left( V_{1}^{2}-V_{2}^{2} \right)}{L} \right)^{1/2}\]
4. \[\left( \frac{C\left( V_{1}-V_{2} \right)^{2}}{L} \right)^{1/2}\]
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Question 18: moderate

The readings of ammeter and voltmeter in the following circuit are respectively :-

1. 2A, 200V
2. 1.5A, 100V
3. 2.7A, 220V
4. 2.2A, 220V
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Question 19: easy

Which one of the following curves represents the variation of impedence (Z) with frequency f in series LCR circuit :-

1.
2.
3.
4.
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Question 20: moderate

For given circuit, find effective impedance for frequencies much higher than resonating
frequency.

1. R1 + R2
2. R2 + R3
3. R1 + R3
4. R1 + R2 + R3
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