Solved papers for NEET Physics Alternating Current / प्रत्यावर्ती धारा NEET PYQ-Alternating Current

done NEET PYQ-Alternating Current Total Questions - 22

• question_answer1) A wire of resistance R is connected in series with an inductor of reactance $\omega L$.  Then quality factor of RL circuit is:                                                                                                                                               [AIPMT 2000]

A)
$\frac{R}{\omega L}$

B)
$\frac{\omega L}{R}$

C)
$\frac{R}{\sqrt{{{R}^{2}}+{{\omega }^{2}}{{L}^{2}}}}$

D)
$\frac{\omega L}{\sqrt{{{R}^{2}}+{{\omega }^{2}}{{L}^{2}}}}$

• question_answer2) For a series LCR circuit, the power loss at resonance is:                              [AIPMT 2002]

A)
$\frac{{{V}^{2}}}{\omega L-\frac{1}{\omega C}}$

B)
${{I}^{2}}\,C\,\omega$

C)
${{I}^{2}}R$

D)
$\frac{{{V}^{2}}}{\omega C}$

• question_answer3) The peak voltage in the output of a half-wave diode rectifier fed with a sinusoidal signal without filter is 10V. The DC component of the output voltage is:                                                                [AIPMT (S) 2004]

A)
$10/\sqrt{2}\,V$

B)
$10/\pi \,\,V$

C)
$-10\,\,V$

D)
$20/\pi \,\,V$

• question_answer4) 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 ${{45}^{o}}$. The value of C is:                                                                                           [AIPMT (S) 2005]

A)
$\frac{1}{2\pi f\,(2\pi fL+R)}$

B)
$\frac{1}{\pi f\,(2\pi fL+R)}$

C)
$\frac{1}{2\pi f\,(2\pi fL-R)}$

D)
$\frac{1}{\pi f\,(2\pi fL-R)}$

• question_answer5) A coil of inductive reactance $31\,\,\Omega$ has a resistance of $8\,\,\Omega$. It is placed in series with a condenser of capacitative reactance $25\,\,\Omega$. The combination is connected to an a.c. soruce of 110 V. The power factor of the circuit is:                                                                                                          [AIPMT (S) 2006]

A)
0.56

B)
0.64

C)
0.80

D)
0.33

• question_answer6) What is the value of inductance I for which the current is a maximum in a series LCR circuit with $C=10\,\mu F$ and to $\omega =1000\,{{s}^{-1}}$?                                                                                       [AIPMT (S) 2007]

A)
100 mH

B)
1 mH

C)
Cannot be calculated unless R is known

D)
10 mH

• question_answer7)  In an AC circuit the emf (e) and the current (i) at any instant are given respectively by  [AIPMPT (S) 2008] $e={{E}_{0}}\sin \omega t$ $i={{I}_{0}}\sin (\omega t-\phi )$ The average power in the circuit over one cycle of AC is

A)
$\frac{{{E}_{0}}{{I}_{0}}}{2}$

B)
$\frac{{{E}_{0}}{{I}_{0}}}{2}\sin \phi$

C)
$\frac{{{E}_{0}}{{I}_{0}}}{2}\cos \phi$

D)
${{E}_{0}}{{I}_{0}}$

• question_answer8)  The rms value of potential difference V shown in the figure is                        [AIPMT (M) 2011]

A)
${{V}_{0}}$

B)
$\frac{{{V}_{0}}}{\sqrt{2}}$

C)
$\frac{{{V}_{0}}}{2}$

D)
$\frac{{{V}_{0}}}{\sqrt{3}}$

• question_answer9) A coil has resistance $30\,\,\Omega$ and inductive reactance $20\,\,\Omega$ at 50 Hz frequency. If an AC source of 200 V, 100 Hz, is connected across the coil, the current in the coil will be                             [AIPMT (M) 2011]

A)
4.0 A

B)
8.0 A

C)
$\frac{20}{\sqrt{12}}A$

D)
2.0 A

• question_answer10) A planet moving along an elliptical orbit is closest to the sun at a distance ${{r}_{1}}$ and farthest away at a distance of ${{r}_{2}}$. If ${{v}_{1}}$ and ${{r}_{2}}$ are the linear velocities at these points respectively, then the ratio $\frac{{{v}_{1}}}{{{v}_{2}}}$ is                                                                               [AIPMT (S) 2011]

A)
${{r}_{2}}/{{r}_{1}}$

B)
${{({{r}_{2}}/{{r}_{1}})}^{2}}$

C)
${{r}_{1}}/{{r}_{2}}$

D)
${{({{r}_{1}}/{{r}_{2}})}^{2}}$

• question_answer11) In an AC circuit an alternating voltage $e=200\sqrt{2}\sin \,100\,t$ volt is connected to a capacitor of capacity $1\,\mu F$. The $rms$ value of the current in the circuit is                                                                    [AIPMT (S) 2011]

A)
100 mA

B)
200 mA

C)
20 mA

D)
10 mA

• question_answer12) A missile is fired for maximum range with a initial velocity of 20 m/s. If $g=10\text{ }m/{{s}^{2}},$ the range of the missile is                                                                                                                                     [AIPMT (S) 2011]

A)
50 m

B)
60 m

C)
20 m

D)
40 m

• question_answer13) The instantaneous values of alternating current and voltages in a circuit are given as $i=\frac{1}{\sqrt{2}}\sin (100\pi t)$ ampere $e=\frac{1}{\sqrt{2}}\sin (100\pi t+\pi /3)$ volt                                       [AIPMT (M) 2012] The average power in Watts consumed in the circuit is

A)
$\frac{1}{4}$

B)
$\frac{\sqrt{3}}{4}$

C)
$\frac{1}{2}$

D)
$\frac{1}{8}$

• question_answer14) In an electrical circuit R, L, C and an AC voltage source are all connected in series. When L is removed from the circuit, the phase difference between the voltage and the current in the circuit is $\pi /3$. If instead, C is removed from the circuit, the phase difference is again $\pi /3$. The power factor of the circuit is                                     [AIPMT (S) 2012]

A)
1/2

B)
$1/\sqrt{2}$

C)
1

D)
$\sqrt{3}/2$

• question_answer15) A coil of self-inductance L is connected in series with a bulb - B and an AC source.  Brightness of the bulb decreases when                                                                                                                                                [NEET 2013]

A)
frequency of the AC source is decreased

B)
number of turns in the coil is reduced

C)
a capacitance of reactance ${{X}_{C}}={{X}_{L}}$ is included in the same circuit

D)
an iron rod is inserted in the coil

• question_answer16) A resistance 'R' draws power 'P' when connected to an AC source. If an inductance such that the impedance of the circuit becomes 'Z' the power drawn will the                                                                                   [NEET  2015]

A)
$P{{\left( \frac{R}{Z} \right)}^{2}}$

B)
$P\sqrt{\frac{R}{Z}}$

C)
$P\left( \frac{R}{Z} \right)$

D)
P

• question_answer17)  A series R-C circuit is connected to an alternating voltage source. Consider two situations:         [NEET (Re) 2015] 1. When capacitor is air filled. 2. When capacitor is mica filled. Current through resistor is i and voltage across capacitor is V then

A)
${{V}_{a}}<{{V}_{b}}$

B)
${{V}_{a}}>{{V}_{b}}$

C)
${{i}_{a}}>{{i}_{b}}$

D)
${{V}_{a}}={{V}_{b}}$

• question_answer18) An inductor 20 mH, a capacitor $50\,\mu F$ and a resistor $40\,\,\Omega$ are connected in series across a source of emf $V=10\text{ }\sin \text{ }340t$. The power loss in A.C. circuit is :-                                    [NEET - 2016]

A)
0.51 W

B)
0.67 W

C)
0.76 W

D)
0.89 W

• question_answer19) An inductor 20 mH, a capacitor $100\text{ }\mu \text{F}$ and a resistor $50\text{ }\Omega$are connected in series across a source of emf, V = 10 sin 314 t. The power loss in the circuit is                                                         [NEET - 2018]

A)
2.74 W

B)
0.43 W

C)
0.79 W

D)
1.13 W

• question_answer20) A small signal voltage $V(t)\text{ }=\text{ }{{V}_{0}}\,\sin \omega t$ is applied across an ideal capacitor C

A)
Current $I(t),$ lags voltage $V\left( t \right)$ by ${{90}^{o}}$.

B)
Over a full cycle the capacitor C does not consume any energy from the voltage source.

C)
Current $I(t)$ is in phase with voltage $V(t)$.

D)
Current $I(t)$ leads voltage $V(t)$ by $\text{18}{{\text{0}}^{o}}$.

• question_answer21) A series LCR circuit is connected to an ac voltage source. When L is removed from the circuit, the phase difference between current and voltage is $\frac{\pi }{3}$. If instead C is removed from the circuit, the phase difference is again $\frac{\pi }{3}$between current and voltage. The power factor of the circuit is:                        [NEET 2020]

A)
0.5

B)
1.0

C)
-1.0

D)
zero

• question_answer22) A $40\,\,\mu F$capacitor is connected to a 200 V, 50 Hz ac supply. The rms value of the current in the circuit is, nearly:                                                                                                                                 [NEET 2020]

A)
2.05 A

B)
2.5 A

C)
25.1 A

D)
1.7 A