JEE Main

Physics

Alternating Current and Electromagnetic Induction

Previous Years Questions

## MCQ (Single Correct Answer)

The ratio of average electric energy density and total average energy density of electromagnetic wave is :

Match List - I with List - II :
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Match List I with List II
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An alternating voltage source $\mathrm{V}=260 \sin (628 \mathrm{t}$ ) is connected across a pure inductor of $5 \mathrm{mH}$ Inductive reactance in th...

If $$\mathrm{R}, \mathrm{X}_{\mathrm{L}}$$, and $$\mathrm{X}_{\mathrm{C}}$$ represent resistance, inductive reactance and capacitive reactance. Then w...

In the given circuit, rms value of current $\left(I_{\mathrm{rms}}\right)$ through the resistor $R$ is:
...

In a series LR circuit with $$\mathrm{X_L=R}$$, power factor P1. If a capacitor of capacitance C with $$\mathrm{X_C=X_L}$$ is added to the circuit the...

Given below are two statements :
Statement I : Electromagnetic waves are not deflected by electric and magnetic field.
Statement II : The amplitude of...

For the given figures, choose the correct options :
...

Find the mutual inductance in the arrangement, when a small circular loop of wire of radius '$$R$$' is placed inside a large square loop of wire of si...

A wire of length 1m moving with velocity 8 m/s at right angles to a magnetic field of 2T. The magnitude of induced emf, between the ends of wire will ...

Match List I with List II
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An electromagnetic wave is transporting energy in the negative $$z$$ direction. At a certain point and certain time the direction of electric field of...

In an LC oscillator, if values of inductance and capacitance become twice and eight times, respectively, then the resonant frequency of oscillator bec...

The electric field and magnetic field components of an electromagnetic wave going through vacuum is described by
$$\mathrm{{E_x} = {E_o}\sin (kz - \om...

A metallic rod of length 'L' is rotated with an angular speed of '$$\omega$$' normal to a uniform magnetic field 'B' about an axis passing through one...

A conducting circular loop of radius $$\frac{10}{\sqrt\pi}$$ cm is placed perpendicular to a uniform magnetic field of 0.5 T. The magnetic field is de...

In $$\overrightarrow E $$ and $$\overrightarrow K $$ represent electric field and propagation vectors of the EM waves in vacuum, then magnetic field v...

A circuit element $$\mathrm{X}$$ when connected to an a.c. supply of peak voltage $$100 \mathrm{~V}$$ gives a peak current of $$5 \mathrm{~A}$$ which ...

An alternating emf $$\mathrm{E}=440 \sin 100 \pi \mathrm{t}$$ is applied to a circuit containing an inductance of $$\frac{\sqrt{2}}{\pi} \mathrm{H}$$....

A coil of inductance 1 H and resistance $$100 \,\Omega$$ is connected to a battery of 6 V. Determine approximately :
(a) The time elapsed before the c...

A transformer operating at primary voltage $$8 \,\mathrm{kV}$$ and secondary voltage $$160 \mathrm{~V}$$ serves a load of $$80 \mathrm{~kW}$$. Assumin...

The equation of current in a purely inductive circuit is $$5 \sin \left(49\, \pi t-30^{\circ}\right)$$. If the inductance is $$30 \,\mathrm{mH}$$ then...

A series LCR circuit has $$\mathrm{L}=0.01\, \mathrm{H}, \mathrm{R}=10\, \Omega$$ and $$\mathrm{C}=1 \mu \mathrm{F}$$ and it is connected to ac voltag...

A direct current of $$4 \mathrm{~A}$$ and an alternating current of peak value $$4 \mathrm{~A}$$ flow through resistance of $$3\, \Omega$$ and $$2\,\O...

The oscillating magnetic field in a plane electromagnetic wave is given by $$B_{y}=5 \times 10^{-6} \sin 1000 \pi\left(5 x-4 \times 10^{8} t\right) T$...

The magnetic field of a plane electromagnetic wave is given by :
$$
\overrightarrow{\mathrm{B}}=2 \times 10^{-8} \sin \left(0.5 \times 10^{3} x+1.5 \t...

In a series $$L R$$ circuit $$X_{L}=R$$ and power factor of the circuit is $$P_{1}$$. When capacitor with capacitance $$C$$ such that $$X_{L}=X_{C}$$ ...

The electric current in a circular coil of 2 turns produces a magnetic induction B1 at its centre. The coil is unwound and in rewound into a circular ...

Light wave travelling in air along x-direction is given by $${E_y} = 540\sin \pi \times {10^4}(x - ct)\,V{m^{ - 1}}$$. Then, the peak value of magnet...

When you walk through a metal detector carrying a metal object in your pocket, it raises an alarm. This phenomenon works on :

To increase the resonant frequency in series LCR circuit,

A small square loop of wire of side $$l$$ is placed inside a large square loop of wire $$\mathrm{L}(\mathrm{L}>>l)$$. Both loops are coplanar an...

The rms value of conduction current in a parallel plate capacitor is $$6.9 \,\mu \mathrm{A}$$. The capacity of this capacitor, if it is connected to $...

An expression for oscillating electric field in a plane electromagnetic wave is given as Ez = 300 sin(5$$\pi$$ $$\times$$ 103x $$-$$ 3$$\pi$$ $$\times...

In series RLC resonator, if the self inductance and capacitance become double, the new resonant frequency (f2) and new quality factor (Q2) will be :
(...

For a series LCR circuit, I vs $$\omega$$ curve is shown :
(a) To the left of $$\omega$$r, the circuit is mainly capacitive.
(b) To the left of $$\ome...

An EM wave propagating in x-direction has a wavelength of 8 mm. The electric field vibrating y-direction has maximum magnitude of 60 Vm$$-$$1. Choose ...

If L, C and R are the self inductance, capacitance and resistance respectively, which of the following does not have the dimension of time?

Given below are two statements :
Statement I : A time varying electric field is a source of changing magnetic field and vice-versa. Thus a disturbance...

The current flowing through an ac circuit is given by
I = 5 sin(120$$\pi$$t)A
How long will the current take to reach the peak value starting from zer...

Two coils of self inductance L1 and L2 are connected in series combination having mutual inductance of the coils as M. The equivalent self inductance ...

The magnetic flux through a coil perpendicular to its plane is varying according to the relation $$\phi = (5{t^3} + 4{t^2} + 2t - 5)$$ Weber. If the ...

If Electric field intensity of a uniform plane electromagnetic wave is given as $$E = - 301.6\sin (kz - \omega t){\widehat a_x} + 452.4\sin (kz - \om...

A sinusoidal voltage V(t) = 210 sin 3000 t volt is applied to a series LCR circuit in which L = 10 mH, C = 25 $$\mu$$F and R = 100 $$\Omega$$. The pha...

The electromagnetic waves travel in a medium at a speed of 2.0 $$\times$$ 108 m/s. The relative permeability of the medium is 1.0. The relative permit...

Match List-I with List-II.
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If wattless current flows in the AC circuit, then the circuit is :

The electric field in an electromagnetic wave is given by E = 56.5 sin $$\omega$$(t $$-$$ x/c) NC$$-$$1. Find the intensity of the wave if it is propa...

Given below are two statements :
Statement I : The reactance of an ac circuit is zero. It is possible that the circuit contains a capacitor and an ind...

A resistance of 40 $$\Omega$$ is connected to a source of alternating current rated 220 V, 50 Hz. Find the time taken by the current to change from it...

A plane electromagnetic wave travels in a medium of relative permeability 1.61 and relative permittivity 6.44. If magnitude of magnetic intensity is 4...

For the given circuit the current i through the battery when the key in closed and the steady state has been reached is __________....

Statement - I :To get a steady dc output from the pulsating voltage received from a full wave rectifier we can connect a capacitor across the output p...

A small square loop of side 'a' and one turn is placed inside a larger square loop of side b and one turn (b >> a). The two loops are coplanar w...

In an ac circuit, an inductor, a capacitor and a resistor are connected in series with XL = R = XC. Impedance of this circuit is :...

Electric field in a plane electromagnetic wave is given by E = 50 sin(500x $$-$$ 10 $$\times$$ 1010 t) V/m The velocity of electromagnetic wave in thi...

In the given circuit the AC source has $$\omega$$ = 100 rad s-1. Considering the inductor and capacitor to be ideal, what will be the current I flowin...

An inductor coil stores 64 J of magnetic field energy and dissipates energy at the rate of 640 W when a current of 8A is passed through it. If this co...

A series LCR circuit driven by 300 V at a frequency of 50 Hz contains a resistance R = 3 k$$\Omega$$, an inductor of inductive reactance XL = 250 $$\p...

A 100$$\Omega$$ resistance, a 0.1 $$\mu$$F capacitor and an inductor are connected in series across a 250 V supply at variable frequency. Calculate th...

A 0.07 H inductor and a 12$$\Omega$$ resistor are connected in series to a 220V, 50 Hz ac source. The approximate current in the circuit and the phase...

A 10 $$\Omega$$ resistance is connected across 220V $$-$$ 50 Hz AC supply. The time taken by the current to change from its maximum value to the rms v...

In a circuit consisting of a capacitance and a generator with alternating emf Eg = Eg0 sin$$\omega$$t, VC and IC are the voltage and current. Correct ...

Match List - I with List - II
List - I
List - II
(a)
$$\omega L > {1 \over {\omega C}}$$
(i)
Current ...

For a series LCR circuit with R = 100 $$\Omega$$, L = 0.5 mH and C = 0.1 pF connected across 220V$$-$$50 Hz AC supply, the phase angle between current...

AC voltage V(t) = 20 sin$$\omega$$t of frequency 50 Hz is applied to a parallel plate capacitor. The separation between the plates is 2 mm and the are...

In a series LCR circuit, the inductive reactance (XL) is 10$$\Omega$$ and the capacitive reactance (XC) is 4$$\Omega$$. The resistance (R) in the circ...

The time taken for the magnetic energy to reach 25% of its maximum value, when a solenoid of resistance R, inductance L is connected to a battery, is ...

In a series LCR resonance circuit, if we change the resistance only, from a lower to higher value :

An AC source rated 220 V, 50 Hz is connected to a resistor. The time taken by the current to change from its maximum to the rms value is :

Match List - I with List - II
List - I
List - II
(a)
Phase difference between current and voltage in a purely re...

What happens to the inductive reactance and the current in a purely inductive circuit if the frequency is halved?

An AC current is given by I = I1 sin$$\omega$$t + I2 cos$$\omega$$t. A hot wire ammeter will give a reading :

For the given circuit, comment on the type of transformer used....

An RC circuit as shown in the figure is driven by a AC source generating a square wave. The output wave pattern monitored by CRO would look close to :...

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

An alternating current is given by the equation i = i1 sin $$\omega$$t + i2 cos $$\omega$$t. The rms current will be :

An LCR circuit contains resistance of 110$$\Omega$$ and a supply of 220 V at 300 rad/s angular frequency. If only capacitance is removed from the circ...

Match List I with List II.
List I
List II
(a)
Rectifier
(i)
Used either for stepping up or stepping down...

The angular frequency of alternating current in a L-C-R circuit is 100 rad/s. The components connected are shown in the figure. Find the value of indu...

The current (i) at time t = 0 and t = $$\infty $$ respectively for the given circuit is :...

Figure shows a circuit that contains four identical resistors with resistance R = 2.0$$\Omega$$, two identical inductors with inductance L = 2.0 mH an...

An AC circuit has R= 100 $$\Omega $$, C = 2 $$\mu $$F and L = 80 mH, connected in series. The quality factor of the
circuit is :

A series L-R circuit is connected to a battery of emf V. If the circuit is switched on at t = 0, then
the time at which the energy stored in the induc...

Choose the correct option relating wave lengths of different parts of electromagnetic wave spectrum:

The electric field of a plane electromagnetic wave propagating along the x direction in vacuum is
$$\overrightarrow E = {E_0}\widehat j\cos \left( {\...

The magnetic field of a plane electromagnetic wave is
$$\overrightarrow B = 3 \times {10^{ - 8}}\sin \left[ {200\pi \left( {y + ct} \right)} \right]\...

A 750 Hz, 20 V (rms) source is connected to a
resistance of 100 $$\Omega $$, an inductance of 0.1803 H
and a capacitance of 10 $$\mu $$F all in series...

In a plane electromagnetic wave, the directions
of electric field and magnetic field are
represented by $$\widehat k$$ and $$2\widehat i - 2\widehat j...

An inductance coil has a reactance of 100 $$\Omega $$.
When an AC signal of frequency 1000 Hz is
applied to the coil, the applied voltage leads
the cu...

A plane electromagnetic wave, has frequency
of 2.0 $$ \times $$ 1010 Hz and its energy density is
1.02 $$ \times $$ 10–8 J/m3 in vacuum. The amplitude...

In LC circuit the inductance L = 40 mH and
capacitance C = 100 $$\mu $$F. If a voltage
V(t) = 10sin(314t) is applied to the circuit, the
current in th...

A shown in the figure, a battery of emf $$\varepsilon $$ is
connected to an inductor L and resistance R in
series. The switch is closed at t = 0. The ...

An emf of 20 V is applied at time t = 0 to a circuit containing in series 10 mH inductor and 5 $$\Omega $$
resistor. The ratio of the currents at time...

Consider a circular coil of wire carrying constant current I, forming a magnetic dipole. The magnetic flux through an infinite plane that contains the...

A long solenoid of radius R carries a time (t) - dependent current I(t)=I0t(1 - t). A ring of radius 2R is placed coaxially near its middle. During th...

A LCR circuit behaves like a damped harmonic oscillator. Comparing it with a physical spring-mass damped oscillator having damping constant 'b', the c...

Consider the LR circuit shown in the figure. If the switch S is closed at t = 0 then the amount of charge that
passes through the battery between t = ...

A plane electromagnetic wave having a frequency v = 23.9 GHz propagates along the positive z-direction in
free space. The peak value of the Electric F...

A coil of self inductance 10 mH and resistance 0.1 $$\Omega $$ is connected through a switch to a battery of internal
resistance 0.9 $$\Omega $$. Afte...

The electric field of a plane electromagnetic
wave is given by
$$\overrightarrow E = {E_0}\widehat i\cos (kz)cos(\omega t)$$ The corresponding magnet...

A transformer consisting of 300 turns in the
primary and 150 turns in the secondary gives
output power of 2.2 kW. If the current in the
secondary coil...

A very long solenoid of radius R is carrying
current I(t) = kte–at(k > 0), as a function of time
(t $$ \ge $$ 0). counter clockwise current is take...

The total number of turns and cross-section area
in a solenoid is fixed. However, its length L is varied
by adjusting the separation between windings....

A circuit connected to an ac source of emf
e = e0sin(100t) with t in seconds, gives a phase
difference of $$\pi $$/4 between the emf e and
current i. ...

A 20 Henry inductor coil is connected to a
10 ohm resistance in series as shown in figure.
The time at which rate of dissipation of energy
(joule's he...

An alternating voltage v(t) = 220 sin 100 $$\pi $$t volt
is applied to a purely resistance load of 50$$\Omega $$ .
The time taken for the current to r...

A 10 m long horizontal wire extends from North East to South West. It is falling with a speed of 5.0 ms–1, at right angles to the horizontal component...

A paramagnetic material has 1028 atoms/m3. Its magnetic susceptibility at temperature 350 K is 2.8 $$ \times $$ 10–4. Its susceptibility at 300 K is :...

In the above circuit, C = $${{\sqrt 3 } \over 2}$$$$\mu $$F, R2 = 20 $$\Omega $$, L = $${{\sqrt 3 } \over {10}}$$ H and R1 = 10 $$\Omega $$. Current i...

A 27 mW laser beam has a cross-sectional area of 10 mm2. The magnitude of the maximum electric field in this electromagnetic wave is given by :
[Given...

A paramagnetic substance in the form of a cube with sides 1 cm has a magnetic dipole moment of 20 $$ \times $$ 10–6 J/ T when a magnetic intensity of ...

An electromagnetic wave of intensity 50 Wm–2 enters in a medium of refractive index 'n' without any loss. The ratio of the magnitudes of electric, and...

The self induced emf of a coil is 25 volts. When the current in it is changed at uniform rate from 10 A to 25 A in 1s, the change in the energy of the...

The electric field of a plane polarized electromagnetic wave in free space at time t = 0 is given by an expression $$\overrightarrow E \left( {x,y} \r...

If the magnetic field of a plane electromagnetic wave is given by (the speed of light = 3 × 108 B = 100 × 10–6
sin $$\left[ {2\pi \times 2 \times {{...

A power transmission line feeds input power at 2300 V to a srep down transformer with its primary windings having 4000 turns. The output power is deli...

A series AC circuit containing an inductor (20 mH), a capacitor (120 $$\mu $$F) and a resistor (60 $$\Omega $$) is driven by an AC source of 24V/50 Hz...

A coil of cross-sectional area A having n turns is placed in a uniform magnetic field B. When it is rotated with an angular velocity $$\omega ,$$ the ...

A power transmission line feeds input power at 2300 V to a step down transformer with its primary windings having 4000 turns, giving the output power...

A plane electromagnetic wave of wavelength $$\lambda $$ has an intensity I. It is propagatting along the positive Y-direction. The allowed expression...

In an a.c. circuit, the instantaneous e.m.f. and current are given by
e = 100 sin 30 t
i = 20 sin $$\left( {30t - {\pi \over 4}} \right)$$
In one cy...

For an RLC circuit driven with voltage of amplitude vm and frequency $${\omega _0}$$ = $${1 \over {\sqrt {LC} }}$$ the current exhibits resonance. The...

An EM wave from air enters a medium. The electric fields are
$$\overrightarrow {{E_1}} $$ = $${E_{01}}\widehat x\cos \left[ {2\pi v\left( {{z \over c}...

A copper rod of mass m slides under gravity on two smooth parallel rails, with separation l and set at an angle of $$\theta $$ with the horizontal. At...

At the center of a fixed large circular coil of radius R, a much smaller circular coil of radius r is placed. The two coils are concentric and are in ...

A plane polarized monochromatic EM wave is traveling in vacuum along z direction such that at t = t1 it is found that the electric field is zero at a ...

A monochromatic beam of light has a frequency $$v = {3 \over {2\pi }} \times {10^{12}}Hz$$ and is propagating along the direction $${{\widehat i + \wi...

An ideal capacitor of capacitance $$0.2\,\mu F$$ is charged to a potential difference of $$10$$ $$V.$$ The charging battery is then disconnected. The ...

A sinusoidal voltage of peak value 283 V and angular frequency 320/s is applied to a series LCR circuit. Given that R=5 $$\Omega $$, L=25 mH and C=100...

The electric field component of a monochromatic radiation is given by
$$\overrightarrow E $$ = 2 E0 $$\widehat i$$ cos kz cos $$\omega $$t
Its magneti...

A small circular loop of wire of radius a is located at the centre of a much larger circular wire loop of radius b. The two loops are in the same plan...

In a coil of resistance 100 $$\Omega $$, a current is induced by changing
the magnetic flux through it as shown in the figure. The
magnitude of change...

A conducting metal circular-wire-loop of radius r is placed perpendicular to a
magnetic field which varies with time as
B = B0e$${^{{{ - t} \over r}}...

Consider an electromagnetic wave propagating in vacuum. Choose the correct
statement :

Microwave oven acts on the principle of :

A series LR circuit is connected to a voltage source with
V(t) = V0 sin$$\Omega $$t. After very large time, current I(t) behaves as
(t0 >> $$...

An arc lamp requires a direct current of
10 A at 80 V to function. If it is connected
to a 220 V (rms), 50 Hz AC supply, the
series inductor needed fo...

Two coaxial solenoids of different radius carry current $$I$$ in the same direction. $$\overrightarrow {{F_1}} $$ be the magnetic force on the inner s...

An $$LCR$$ circuit is equivalent to a damped pendulum. In an $$LCR$$ circuit the capacitor is charged to $${Q_0}$$ and then connected to the $$L$$ and...

An inductor $$(L=0.03$$ $$H)$$ and a resistor $$\left( {R = 0.15\,k\Omega } \right)$$ are connected in series to a battery of $$15V$$ $$EMF$$ in a cir...

A red $$LED$$ emits light at $$0.1$$ watt uniformly around it. The amplitude of the electric field of the light at a distance of $$1$$ $$m$$ from the ...

In the circuit shown here, the point $$'C'$$ is kept connected to point $$'A'$$ till the current flowing through the circuit becomes constant. Afterw...

During the propagation of electromagnetic waves in a medium:

Match List - $$1$$ (Electromagnetic wave type ) with List - $$2$$ (Its association/application) and select the correct option from the choices given ...

A circular loop of radius $$0.3$$ $$cm$$ lies center of the small loop is on the axis of the bigger loop. The distance between their centers is $$15$$...

A metallic rod of length $$'\ell '$$ is tied to a string of length $$2$$$$\ell $$ and made to rotate with angular speed $$w$$ on a horizontal table w...

In an $$LCR$$ circuit as shown below both switches are open initially. Now switch $${S_1}$$ is closed, $${S_2}$$ kept open. ($$q$$ is charge on the ca...

The magnetic field in a travelling electromagnetic wave has a peak value of $$20$$ $$n$$$$T$$. The peak value of electric field strength is :

A coil is suspended in a uniform magnetic field, with the plane of the coil parallel to the magnetic lines of force. When a current is passed through ...

A fully charged capacitor $$C$$ with initial charge $${q_0}$$ is connected to a coil of self inductance $$L$$ at $$t=0.$$ The time at which the energy...

A boat is moving due east in a region where the earth's magnetic fields is $$5.0 \times {10^{ - 5}}$$ $$N{A^{ - 1}}\,{m^{ - 1}}$$ due north and horizo...

A resistor $$'R'$$ and $$2\mu F$$ capacitor in series is connected through a switch to $$200$$ $$V$$ direct supply. Across the capacitor is a neon bul...

In a series $$LCR$$ circuit $$R = 200\Omega $$ and the voltage and the frequency of the main supply is $$220V$$ and $$50$$ $$Hz$$ respectively. On tak...

A rectangular loop has a sliding connector $$PQ$$ of length $$l$$ and resistance $$R$$ $$\Omega $$ and it is moving with a speed $$v$$ as shown. The s...

In the circuit shown below, the key $$K$$ is closed at $$t=0.$$ The current through the battery is
...

An inductor of inductance $$L=400$$ $$mH$$ and resistors of resistance $${R_1} = 2\Omega $$ and $${R_2} = 2\Omega $$ are connected to a battery of $$e...

Two coaxial solenoids are made by winding thin insulated wire over a pipe of cross-sectional area $$A=$$ $$10\,\,c{m^2}$$ and length $$=20$$ $$cm$$ ....

In an $$a.c.$$ circuit the voltage applied is $$E = {E_0}\,\sin \,\omega t.$$ The resulting current in the circuit is $$I = {I_0}\sin \left( {\omega t...

An ideal coil of $$10H$$ is connected in series with a resistance of $$5\Omega $$ and a battery of $$5V$$. $$2$$ second after the connection is made, ...

Which of the following units denotes the dimension $${{M{L^2}} \over {{Q^2}}}$$, where $$Q$$ denotes the electric charge?

In a series resonant $$LCR$$ circuit, the voltage across $$R$$ is $$100$$ volts and $$R = 1\,k\Omega $$ with $$C = 2\mu F.$$ The resonant frequency $$...

In an $$AC$$ generator, a coil with $$N$$ turns, all of the same area $$A$$ and total resistance $$R,$$ rotates with frequency $$\omega $$ in a magnet...

The flux linked with a coil at any instant $$'t'$$ is given by
$$\phi = 10{t^2} - 50t + 250$$
The induced $$emf$$ at $$t=3s$$ is

An inductor $$(L=100$$ $$mH)$$, a resistor $$\left( {R = 100\,\Omega } \right)$$ and a battery $$\left( {E = 100V} \right)$$ are initially connected i...

The $$rms$$ value of the electric field of the light coming from the Sun is $$720$$ $$N/C.$$ The average total energy density of the electromagnetic w...

The self inductance of the motor of an electric fan is $$10$$ $$H$$. In order to impart maximum power at $$50$$ $$Hz$$, it should be connected to a ca...

A coil of inductance $$300$$ $$mH$$ and resistance $$2\,\Omega $$ is connected to a source of voltage $$2$$ $$V$$. The current reaches half of its ste...

A circuit has a resistance of $$12$$ $$ohm$$ and an impedance of $$15$$ $$ohm$$. The power factor of the circuit will be

The phase difference between the alternating current and $$emf$$ is $${\pi \over 2}.$$ Which of the following cannot be the constituent of the circui...

One conducting $$U$$ tube can slide inside another as shown in figure, maintaining electrical contacts between the tubes. The magnetic field $$B$$ is ...

Alternating current can not be measured by $$D.C.$$ ammeter because

In an $$LCR$$ series $$a.c.$$ circuit, the voltage across each of the components, $$L,C$$ and $$R$$ is $$50V$$. The voltage across the $$L.C$$ combina...

A coil having $$n$$ turns and resistance $$R\Omega $$ is connected with a galvanometer of resistance $$4R\Omega .$$ This combination is moved in time ...

In a uniform magnetic field of induction $$B$$ a wire in the form of a semicircle of radius $$r$$ rotates about the diameter of the circle with an ang...

A metal conductor of length $$1$$ $$m$$ rotates vertically about one of its ends at angular velocity $$5$$ radians per second. If the horizontal comp...

In a $$LCR$$ circuit capacitance is changed from $$C$$ to $$2$$ $$C$$. For the resonant frequency to remain unchaged, the inductance should be changed...

Two coils are placed close to each other. The mutual inductance of the pair of coils depends upon

In an oscillating $$LC$$ circuit the maximum charge on the capacitor is $$Q$$. The charge on the capacitor when the energy is stored equally between t...

When the current changes from $$ + 2A$$ to $$-2A$$ in $$0.05$$ second, an $$e.m.f.$$ of $$8$$ $$V$$ is inducted in a coil. The coefficient of self- in...

The core of any transformer is laminated so as to

The power factor of $$AC$$ circuit having resistance $$(R)$$ and inductance $$(L)$$ connected in series and an angular velocity $$\omega $$ is

In a transformer, number of turns in the primary coil are $$140$$ and that in the secondary coil are $$280.$$ If current in primary coil is $$4A,$$ th...

The inductance between $$A$$ and $$D$$ is
...

A conducting square loop of side $$L$$ and resistance $$R$$ moves in its plane with a uniform velocity $$v$$ perpendicular to one of its sides. A magn...

Which of the following are not electromagnetic waves?

## Numerical

A square shaped coil of area $$70 \mathrm{~cm}^{2}$$ having 600 turns rotates in a magnetic field of $$0.4 ~\mathrm{wbm}^{-2}$$, about an axis which i...

A series LCR circuit is connected to an ac source of $$220 \mathrm{~V}, 50 \mathrm{~Hz}$$. The circuit contain a resistance $$\mathrm{R}=100 ~\Omega$$...

A series $\mathrm{LCR}$ circuit consists of $\mathrm{R}=80 \Omega, \mathrm{X}_{\mathrm{L}}=100 \Omega$, and $\mathrm{X}_{\mathrm{C}}=40 \Omega$. The i...

An inductor of $$0.5 ~\mathrm{mH}$$, a capacitor of $$20 ~\mu \mathrm{F}$$ and resistance of $$20 ~\Omega$$ are connected in series with a $$220 \math...

In an ac generator, a rectangular coil of 100 turns each having area $14 \times 10^{-2} \mathrm{~m}^{2}$ is rotated at $360 ~\mathrm{rev} / \mathrm{mi...

As per the given figure, if $$\frac{\mathrm{dI}}{\mathrm{dt}}=-1 \mathrm{~A} / s$$ then the value of $$\mathrm{V}_{\mathrm{AB}}$$ at this instant wil...

An inductor of inductance 2 $$\mathrm{\mu H}$$ is connected in series with a resistance, a variable capacitor and an AC source of frequency 7 kHz. The...

A certain elastic conducting material is stretched into a circular loop. It is placed with its plane perpendicular to a uniform magnetic field B = 0.8...

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 reacta...

An LCR series circuit of capacitance 62.5 nF and resistance of 50 $$\Omega$$, is connected to an A.C. source of frequency 2.0 kHz. For maximum value o...

Three identical resistors with resistance R = 12$$\Omega$$ and two identical inductors with self inductance L = 5 mH are connected to an ideal battery...

In the circuit shown in the figure, the ratio of the quality factor and the band width is ___________ s.
...

A capacitor of capacitance 500 $$\mu$$F is charged completely using a dc supply of 100 V. It is now connected to an inductor of inductance 50 mH to fo...

For the given circuit the current through battery of 6 V just after closing the switch 'S' will be _________ A.
...

The frequencies at which the current amplitude in an LCR series circuit becomes $$\frac{1}{\sqrt{2}}$$ times its maximum value, are $$212\,\mathrm{rad...

A conducting circular loop is placed in $$X-Y$$ plane in presence of magnetic field $$\overrightarrow{\mathrm{B}}=\left(3 \mathrm{t}^{3} \,\hat{j}+3 \...

To light, a $$50 \mathrm{~W}, 100 \mathrm{~V}$$ lamp is connected, in series with a capacitor of capacitance $$\frac{50}{\pi \sqrt{x}} \mu F$$, with $...

In a coil of resistance $$8 \,\Omega$$, the magnetic flux due to an external magnetic field varies with time as $$\phi=\frac{2}{3}\left(9-t^{2}\right)...

The effective current I in the given circuit at very high frequencies will be ___________ A.
...

Magnetic flux (in weber) in a closed circuit of resistance 20 $$\Omega$$ varies with time t(s) at $$\phi$$ = 8t2 $$-$$ 9t + 5. The magnitude of the in...

A series LCR circuit with $$R = {{250} \over {11}}\,\Omega $$ and $${X_L} = {{70} \over {11}}\,\Omega $$ is connected across a 220 V, 50 Hz supply. Th...

An inductor of 0.5 mH, a capacitor of 200 $$\mu$$F and a resistor of 2 $$\Omega$$ are connected in series with a 220 V ac source. If the current is in...

The intensity of the light from a bulb incident on a surface is 0.22 W/m2. The amplitude of the magnetic field in this light-wave is ______________ $$...

In the given circuit, the magnitude of VL and VC are twice that of VR. Given that f = 50 Hz, the inductance of the coil is $${1 \over {K\pi }}$$ mH. T...

An AC source is connected to an inductance of 100 mH, a capacitance of 100 $$\mu$$F and a resistance of 120 $$\Omega$$ as shown in figure. The time in...

A telegraph line of length 100 km has a capacity of 0.01 $$\mu$$F/km and it carries an alternating current at 0.5 kilo cycle per second. If minimum im...

A 220 V, 50 Hz AC source is connected to a 25 V, 5 W lamp and an additional resistance R in series (as shown in figure) to run the lamp at its peak br...

A 10 $$\Omega$$, 20 mH coil carrying constant current is connected to a battery of 20 V through a switch. Now after switch is opened current becomes z...

A 110 V, 50 Hz, AC source is connected in the circuit (as shown in figure). The current through the resistance 55 $$\Omega$$, at resonance in the circ...

In a series LCR circuit, the inductance, capacitance and resistance are L = 100 mH, C = 100 $$\mu$$F and R = 10 $$\Omega$$ respectively. They are conn...

The current in a coil of self inductance 2.0 H is increasing according to I = 2 sin(t2) A. The amount of energy spent during the period when current c...

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 th...

At very high frequencies, the effective impendence of the given circuit will be ________________ $$\Omega$$....

The electric field in an electromagnetic wave is given by E = (50 NC$$-$$1) sin$$\omega$$ (t $$-$$ x/c)The energy contained in a cylinder of volume V ...

An ac circuit has an inductor and a resistor resistance R in series, such that XL = 3R. Now, a capacitor is added in series such that XC = 2R. The rat...

The alternating current is given by $$i = \left\{ {\sqrt {42} \sin \left( {{{2\pi } \over T}t} \right) + 10} \right\}A$$The r.m.s. value of of this cu...

In the given figure the magnetic flux through the loop increases according to the relation $$\phi$$B(t) = 10t2 + 20t, where $$\phi$$B is in milliweber...

Consider an electrical circuit containing a two way switch 'S'. Initially S is open and then T1 is connected to T2. As the current in R = 6$$\Omega$$ ...

Two circuits are shown in the figure (a) & (b). At a frequency of ____________ rad/s the average power dissipated in one cycle will be same in bot...

An inductor of 10 mH is connected to a 20V battery through a resistor of 10 k$$\Omega$$ and a switch. After a long time, when maximum current is set u...

A series LCR circuit of R = 5$$\Omega$$, L = 20 mH and C = 0.5 $$\mu$$F is connected across an AC supply of 250 V, having variable frequency. The powe...

In an LCR series circuit, an inductor 30 mH and a resistor 1 $$\Omega$$ are connected to an AC source of angular frequency 300 rad/s. The value of cap...

A sinusoidal voltage of peak value 250 V is applied to a series LCR circuit, in which R = 8$$\Omega$$, L = 24 mH and C = 60 $$\mu$$F. The value of pow...

In a series LCR resonant circuit, the quality factor is measured as 100. If the inductance is increased by two fold and resistance is decreased by two...

A coil of inductance 2 H having negligible resistance is connected to a source of supply whose voltage is given by V = 3t volt. (where t is in second)...

A transmitting station releases waves of wavelength 960 m. A capacitor of 2.56 $$\mu$$F is used in the resonant circuit. The self inductance of coil n...

A series L-C-R circuit is designed to resonate at an angular frequency $$\omega$$0 = 105 rad/s. The circuit draws 16W power from 120V source at resona...

A common transistor radio set requires 12 V (D.C.) for its operation. The D.C. source is constructed by using a transformer and a rectifier circuit, w...

A resonance circuit having inductance and resistance 2 $$\times$$ 10$$-$$4 H and 6.28$$\Omega$$ respectively oscillates at 10 MHz frequency. The value...

In a series LR circuit, power of 400W is dissipated from a source of 250 V, 50 Hz. The power factor
of the circuit is 0.8. In order to bring the power...

Suppose that intensity of a laser is $${{315} \over \pi }$$ W/m2. The rms electric field, in units of V/m associated
with this source is close to the ...

In a fluorescent lamp choke (a small
transformer) 100 V of reverse voltage is
produced when the choke current changes
uniformly from 0.25 A to 0 in a ...

A loop ABCDEFA of straight edges has six corner points A(0, 0, 0), B(5, 0, 0), C(5, 5, 0), D (0, 5,
0), E(0, 5, 5) and F(0, 0, 5). The magnetic field ...