# Resonance in RLC Circuit

## Trending Questions

**Q.**Ten tuning forks are arranged in increasing order of frequency in such a way that any two nearest tuning forks produce 4 beats/sec. The highest frequency is twice of the lowest. Possible highest and the lowest frequencies are

- 80 and 40
- 100 and 50
- 44 and 22
- 72 and 36

**Q.**A box containing a resistance R, inductance L and a capacitor of capacitance C is connected in series to an alternating source of angular frequency 4 rad/s and a capacitor of capacitance C as shown in the circuit. Box has power factor of 1√3 and the circuit has overall power factor of 1. The impedance of the box is

- 14C
- 34√2C
- √34√2C
- 14√2C

**Q.**

Find the peak current and resonant frequency of the following circuit (as shown in the figure)

$0.2A$and $100Hz$

$2A$and $50Hz$

$2A$and $100Hz$

$0.2A$and $50Hz$

**Q.**25.A coil of self inductance L is connected in series with a bulb B and AC source. Brightness of the bulb decreases when 1)Number of turns in the coil is reduced 2)capacitance of reactance Xl=Xc is included in same circuit 3) Iron Rod is inserted in the coil. 4) Frequency of AC source is decreased

**Q.**The amplifiers A, B and C are connected in series. If the voltage gain of A, B and C are 10, 15 and 20 respectively and input signal 2 mV peak value. Then the output signal voltage’s peak value will be (1) 6 V(2) 5 V(3) 3 V (4) 4 V

**Q.**In a series LCR circuit, the inductance, capacitance and resistance are L=100 mH, C=100 μF and R=10 Ω respectively. They are connected to an AC source of voltage 220 V and frequency of 50 Hz. The approximate value of current in the circuit will be

**Q.**

What is a series resonance circuit?

**Q.**To increase the resonant frequency in series LCR circuit,

- Source frequency should be increased.
- Another resistance should be added in series with the first resistance.
- Another capacitor should be added in series with the first capacitor.
- The source frequency should be decreased.

**Q.**In a LCR circuit having L = 8.0 henry, C=0.5 μF and R = 100 ohm in series. The resonance frequency in per second is

- 600 radian per sec
- 500 radian per sec
- 500 Hz
- 600 Hz

**Q.**A series LCR circuit has L = 1mH, C = 0.1 μF and R = 10 Ω . It is connected across a source of alternating emf of 5V but of variable frequency. Find (i) the frequency at which the impedance is minimum (ii) the current at resonance.

- 1052πHz, 12A
- 1042πHz, 12A
- 1022πHz, 12A
- 1032πHz, 12A

**Q.**As shown in the figure an inductor of inductance 200 mH is connected to an AC source of emf 220 V and frequency 50 Hz. The instantaneous voltage of the source is 0 V when the peak value of current is √aπ A. The value of a is

**Q.**

What is the unit of Capacitive Reactance X_{c}?

mhO

Ohm

Ohm

^{-1}Ohm

^{2}

**Q.**A transistor is used as an amplifier in CB− mode with a load resistance of 5 kΩ the current gain of amplifier is 0.98 and the input resistance is 70 Ω. The voltage gain and power gain respectively are

- 70 ; 68.6
- 80 ; 75.6
- 60 ; 66.6
- 90 ; 96.6

**Q.**An ac circuit consists of an inductor of inductance 0.5 H and a capacitor of capacitance 8 μF in series. The current in the circuit is maximum when the angular frequency of ac source is

- 2×105 rad/sec
- 500 rad/sec
- 4000 rad/sec
- 5000 rad/sec

**Q.**In a series CR circuit shown in figure, the applied voltage is 10 V and the voltage across capacitor is found to be 8 V. Then the voltage across R, and the phase difference between current and the applied voltage will respectively be

- 6 V, tan−1(43)
- 3 V, tan−1(34)
- 6 V, tan−1(53)
- Zero, Zero

**Q.**What is the peak voltage across capacitor at resonance frequency in the given circuit ?

- 10 V
- 100 V
- 5 V
- 50 V

**Q.**A source of frequency f gives 5 beats per second when sounded with a source of frequency 200hz. The second harmonic of frequency 2f of source gives 10 beats per second when sounded with a source of frequency 420hz. The value of f is

**Q.**

If an emitter current is changed by $4mA$, the collector current changes by $3.5mA$. The value of $\beta $ will be:

$7$

$0.875$

$0.5$

$3.5$

**Q.**

R, L and C represent the physical quantities resistance, inductance and capacitance, respectively. Which one of the following combinations has the dimension of frequency?

$\frac{1}{\sqrt{RC}}$

$\frac{R}{L}$

$\frac{1}{LC}$

$\frac{C}{L}$

**Q.**

The maximum resistance which can be made using four resistors each of $2\Omega $ is

$2\Omega $

$4\Omega $

$8\Omega $

$16\Omega $

**Q.**An inductor of inductance 100mH is connected in series with a resistance, a variable capacitance and an AC source of frequency 2.0 kHz. The value of the capacitance so that maximum current may be drawn into the circuit.

- 60 nF
- 63 nF
- 50 nF
- 79 nF

**Q.**In a series circuit C=2μF, L=1 mH and R=10 Ω, when the current in the circuit is maximum, at that time the ratio of the energies stored in the capacitor and the inductor will be

- 1 : 1
- 1 : 2
- 2 : 1
- 1 : 5

**Q.**A uniform wire of length L and mass M is stretched between two fixed points, keeping a tension F.A sound of frequency is impressed on it.Then the maximum vibrational energy is existing in the wire whenis equal to

**Q.**In the circuit shown, the input waveform is given. Which of the following correctly gives the output waveform across RL?

**Q.**For an a-c circuit containing inductor only as shown. The graph of inductive reactance (XL) vs frequency f of an ac

**Q.**The figure show a series LCR circuit with L=5.0H, C=80μF, R=40Ω connected to variable frequency 240 V source. Calculate

(i)The angular frequency of the source which driver the circuit at resonance

(ii) The current at the frequency.

(iii)The rms potential drop across the capacitor at resonance

**Q.**The inductance L (in mH) of the coil which is to be connected in series with a capacitor of 0.3 pF to get an oscillatory resonance frequency of 1 MHz is.

- 8.44mH
- 84.4mH
- 844mH
- 8440mH

**Q.**

What is the natural frequency of an LC oscillator?

**Q.**16. For the series LCR circuit shown , what is the resonance frequency and the amplitude of the current at the resonating frequency

**Q.**Assertion : Eddy currents heat up the core and dissipate electrical energy in the form of heat.

Reason : Eddy currents are always undesirable.

Choose the correct alternative corresponding to the given assertion and reason.

- Both assertion and reason are correct, and reason is the correct explanation of the assertion
- Both assertion and reason are correct, and reason is not the correct explanation of the assertion
- Assertion is correct, but reason is incorrect
- Assertion is incorrect, but reason is correct