JEE Main Physics — Electromagnetism previous year questions with solutions.
The waves emitted when a metal target is bombarded with high energy electrons are
A $20\mathrm{cm}$ long metallic rod is rotated with $210\mathrm{rpm}$ about an axis normal to the rod passing through its one end. The other end of the rod is in contact with a circular metallic ring. A constant and uniform magnetic field $0.2T$ parallel to the axis exists everywhere. The emf developed between the centre and the ring is _________$\mathrm{mV}$. (Take $\pi =\frac{22}{7}$)
An ideal transformer with purely resistive load operates at $12\mathrm{kV}$ on the primary side. It supplies electrical energy to a number of nearby houses at $120V.$ The average rate of energy consumption in the houses served by the transformer is $60\mathrm{kW}.$ The value of resistive load $({R}_{s})$ required in the secondary circuit will be$_________m\Omega .$
A certain elastic conducting material is stretched into a circular loop. It is placed with its plane perpendicular to a uniform magnetic field $B=0.8T$. When released the radius of the loop starts shrinking at a constant rate of $2\mathrm{cm}{s}^{–1}$. The induced emf in the loop at an instant when the radius of the loop is $10\mathrm{cm}$ will be ______ $\mathrm{mV}$.
In the network shown below, the charge accumulated in the capacitor in steady state will be: 
A parallel plate capacitor has plate area $40{\mathrm{cm}}^{2}$ and plates separation $2\mathrm{mm}$. The space between the plates is filled with a dielectric medium of a thickness $1\mathrm{mm}$ and dielectric constant $5$. The capacitance of the system is:
In the given circuit, $rms$ value of current $({I}_{rms})$ through the resistor $R$ is : 
In an LC oscillator, if values of inductance and capacitance become twice and eight times, respectively, then the resonant frequency of oscillator becomes $x$ times its initial resonant frequency ${\omega }_{0}$. The value of $x$ is:
An electron in a hydrogen atom revolves around its nucleus with a speed of $6.76\times {10}^{6}m{s}^{–1}$ in an orbit of radius $0.52Å$. The magnetic field produced at the nucleus of the hydrogen atom is _______ $T$.
A series LCR circuit is connected to an AC source of $220V$, $50\mathrm{Hz}$. 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:
A cubical volume is bounded by the surfaces $x=0,x=a,y=0,y=a,z=0,z=a$. The electric field in the region is given by $\vec{E}={E}_{0}x\hat{i}$. Where ${E}_{0}=4\times {10}^{4}{\mathrm{NC}}^{-1}{m}^{-1}$. If $a=2\mathrm{cm}$, the charge contained in the cubical volume is $Q\times {10}^{–14}C$. The value of $Q$ is ______. (Take ${\epsilon }_{0}=9\times {10}^{-12}{C}^{2}{N}^{-1}{m}^{-2}$)
A parallel plate capacitor with plate area $A$ and plate separation $d$ is filled with a dielectric material of dielectric constant $K=4.$ The thickness of the dielectric material is $x,$ where $x<d.$  Let ${C}_{1}$ and ${C}_{2}$ be the capacitance of the system for $x=\frac{1}{3}d$ and $x=\frac{2d}{3},$ respectively. If ${C}_{1}=2\mu F$, the value of ${C}_{2}$ is _____ $\mu F.$
Match the List-I with List-II. <table class="pyq-table"><tbody><tr><td></td><td>List I</td><td></td><td>List II</td></tr><tr><td>A</td><td>AC generator</td><td>I</td><td>Presence of both L and C</td></tr><tr><td>B</td><td>Transformer</td><td>II</td><td>Electromagnetic Induction</td></tr><tr><td>C</td><td>Resonance phenomenon to occur</td><td>III</td><td>Quality factor</td></tr><tr><td>D</td><td>Sharpness of resonance</td><td>IV</td><td>Mutual Inductance</td></tr></tbody></table>Choose the correct answer from the options given below:
An electron is moving along the positive x-axis. If uniform magnetic field is applied parallel to the negative z-axis, then A.The electron will experience magnetic force along positive y-axis B.The electron will experience magnetic force along negative y-axis C.The electron will not experience any force in magnetic field D.The electron will continue to move along the positive x-axis E.The electron will move along circular path in magnetic field Choose the correct answer from the option given below:
Which of the following are true? A. Speed of light in vacuum is dependent on the direction of propagation. B. Speed of light in a medium is independent of the wavelength of light. C. The speed of light is independent of the motion of the source. D. The speed of light in a medium is independent of intensity. Choose the correct answer from the question given below :
Given below are two statements : Statement I : Electromagnetic waves are not deflected by electric and magnetic field. Statement II : The amplitude of electric field and the magnetic field in electromagnetic waves are related to each other as ${E}_{0}=\sqrt{\frac{{\mu }_{0}}{{\epsilon }_{0}}}{B}_{0}$. In the light of the above statements, choose the correct answer from the options given below:
In an ac generator, a rectangular coil of $100$ turns each having area $14\times {10}^{–2}{m}^{2}$ is rotated at $360\mathrm{rev}{\mathrm{min}}^{-1}$ about an axis perpendicular to a uniform magnetic field of magnitude $3.0T$. The maximum value of the emf produced will be ______ $V$. [Take $\pi =\frac{22}{7}$]
A capacitor of capacitance $C$ is charged to a potential $V$. The flux of the electric field through a closed surface enclosing the positive plate of the capacitor is:
Match List I and List II <table class="pyq-table"><tbody><tr><td></td><td>List I</td><td></td><td>List II</td></tr><tr><td>A</td><td>Microwaves</td><td>I</td><td>Physiotherapy</td></tr><tr><td>B</td><td>UV rays</td><td>II</td><td>Treatment of cancer</td></tr><tr><td>C</td><td>Infra-red rays</td><td>III</td><td>Lasik eye surgery</td></tr><tr><td>D</td><td>X-rays</td><td>IV</td><td>Aircraft navigation</td></tr></tbody></table>Choose the correct answer from the option given below:
Given below are two statements: Statement I: Maximum power is dissipated in a circuit containing an inductor, a capacitor and a resistor connected in series with an $AC$ source, when resonance occurs. Statement II: Maximum power is dissipated in a circuit containing pure resistor due to zero phase difference between current and voltage. In the light of the above statements, choose the correct answer from the options given below:
Given below are two statements : One is labelled as Assertion A and the other is labelled as Reason R. Assertion A : Two metallic spheres are charged to the same potential. One of them is hollow and another is solid, and both have the same radii. Solid sphere will have lower charge than the hollow one. Reason R : Capacitance of metallic spheres depend on the radii of spheres. In the light of the above statements, choose the correct answer from the options given below.
For designing a voltmeter of range $50V$ and an ammeter of range $10\mathrm{mA}$ using a galvanometer which has a coil of resistance $54Ω$ showing a full scale deflection for $1\mathrm{mA}$ as in figure.  (A) for voltmeter $R\approx 50kΩ$ (B) for ammeter $r\approx 0.2Ω$ (C) for ammeter $r\approx 6Ω$ (D) for voltmeter $R\approx 5kΩ$ (E) for voltmeter $R\approx 500Ω$ Choose the correct answer from the options given below:
A plane electromagnetic wave of frequency $20\mathrm{MHz}$ propagates in free space along $x$-direction. At a particular space and time $\vec{E}=6.6\hat{j}V{m}^{-1}$. What is $\vec{B}$ at this point?
As shown in the figure, a network of resistors is connected to a battery of $24V$ with an internal resistance of $3\Omega$. The currents through the resistors ${R}_{4}$ and ${R}_{5}$ are ${I}_{4}$ and ${I}_{5}$ respectively. The values of ${I}_{4}$ and ${I}_{5}$ are: 