List of top Physics Questions on LCR Circuit

A logic circuit provides the output y as per the following truth table:

A	B	Y
0	0	1
0	1	0
1	0	1
1	1	0

The expression for the output Y is:

Output of given circuit represents which logic gate :

Total impedance of a series LCR circuit varies with angular frequency of the AC source connected to it as shown in the graph. The quality factor Q of the series LCR circuit is

A series LCR circuit is connected to an $AC$ source of $220 V , 50 Hz$ The circuit contains a resistance $R =80 \Omega$, an inductor of inductive reactance $X _{ L }=70 \Omega$, and a capacitor of capacitive reactance $X _{ C }=130 \Omega$ The power factor of circuit is $\frac{x}{10}$ The value of $x$ is :

Figure shows a part of an electric circuit. The potentials at the points a, b and c are 30V, 12V and 2V respectively. the currents through the 20 resistors will be.

An LCR series circuit of capacitance \(625\ nF\) and resistance of \(50 \ \Omega\) is connected to an AC source of frequency \(20\ kHz\) For maximum value of amplitude of current in circuit, the value of inductance is ___ \(mH\). (Take \(\pi^2 =10\))

Choose the correct statements from the following:
A. Induced emf opposes any change in the current in a circuit
B. Induced emf in a closed coil can be increased by increasing the number of turns in the coil
C. Varying current in a coil can not induce emf in a neighbouring coil.
D. An LCR circuit has zero impedance at resonant frequency
E. Average power supplied to an inductor over one complete cycle is zero
Choose the correct answer from the options given below:

Match List I with List II

Choose the correct answer from the options given below:

In a series LCR circuit an ac voltage source is connected. When inductor is removed from the circuit, the phase difference between the voltage and the current in the circuit is \(\frac{π}{3}\). If capacitor is removed from the circuit instead of inductor, the phase difference is again \(\frac{π}{3}\). What is the power factor of the circuit?

An oscillating LC circuit consists of a 75 mH inductor and a 1.2 uF capacitor. If the maximum charge to the capacitor is 2.7μC. The maximum current in the circuit will be _____mA.

Given below are two statements :  
Statement I : When the frequency of an a.c. source in a series LCR circuit increases, the current in the circuit first increases, attains a maximum value and then decreases.  
Statement II : In a series LCR circuit, the value of power factor at resonance is one. 
In the light of given statements, choose the most appropriate answer from the options given below:

In series LCR circuit at resonance, the phase difference between voltage and current is

In a fixed-bias common-emitter Circuit.
A. Maintaining \(I_B\) constant will not provide operating-point stability as ẞ changes.
B. IB should not be allowed to change as to maintain \(V_{CB}\) and \(I_C\), constant as ẞ changes.
C. The reverse saturation current Ico doubles for every 10 °C rise in temperature.
D. The value of stability factor \(S=(1+\beta)\)
E. The circuit is highly unstable

Match List I with List II

LIST I (Type of Device)		LIST II (Characteristics/ Application)
A	GTO	I	Triggering Circuit
B	UJT	II	Turn off by negative pulse rate
C	TRIAC	III	High Speed Switching
D	MOSFET	IV	Bidirectional Switching

Choose the correct answer from the options given below:

A combinational logic circuit has three inputs A, B and C and one output Y. The output Y=1. when at least two inputs are 1. otherwise. Y=0. In its minimised SOP realization, the maximum number of two-input terms is:

Match List I with List II

LIST I (Type of Test)		LIST II Quantities to be measured)
A	Open circuit test	I	Copper loss and iron loss
B	Short circuit test	II	Total losses
C	Sumpner's test	III	Iron test
D	Load test	IV	Copper losses

Choose the correct answer from the options given below:

Given below are two statements:
Statement I: A series RLC circuit is said to be in resonance when current delivered by the source is in phase with the source voltage.
Statement II: Power factor of a series RLC is zero, if circuit is in resonance condition.
In the light of the above statements, choose the correct answer from the options given below:

Find \(R_{ equivalent}\) of the given circuit.

There are three planets in circular orbits around a star at a distance a, 9a and 16a respectively. At time t = \(t_0\), the star and the planets are in a straight line. The period of revolution of the closest planet is T. How long after \(t_0\), will they again be in the same line?

The digital circuit shown in below represents:

Three concentric shells A, B and C having surface charge density σ, –σ and σ respectively. The radii of A and B are 2 cm and 3 cm respectively. Electric potential at surface A is V_A and at C is V_C. If V_A = V_C then find the radius of C in cm.

In the given circuit, the current (I) through the battery will be

Ratio of thermal energy released in two resistors R and 3R connected in parallel in an electric circuit is