JEE Main Physics — Electromagnetism previous year questions with solutions.
Two $10\mathrm{cm}$ long, straight wires, each carrying a current of $5A$ are kept parallel to each other. If each wire experienced a force of ${10}^{-5}N$, then separation between the wires is _____ $\mathrm{cm}.$
A resistor develops $300J$ of thermal energy in $15s$, when a current of $2A$ is passed through it. If the current increases to $3A$, the energy developed in $10s$ is _____ $J$.
A $110V,50\mathrm{Hz},\mathrm{AC}$ source is connected in the circuit (as shown in figure). The current through the resistance $55\Omega$, at resonance in the circuit, will be _____$A$. 
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 in electric or magnetic field creates EM waves. Statement II: In a material medium, the EM wave travels with speed $v=\frac{1}{\sqrt{{\mu }_{0}{\epsilon }_{0}}}$. In the light of the above statements, choose the correct answer from the options given below.
A velocity selector consists of electric field $\vec{E}=E\hat{k}$ and magnetic field $\vec{B}=B\hat{j}$ with $B=12\mathrm{mT}$. The value $E$ required for an electron of energy $728\mathrm{eV}$ moving along the positive $x$-axis to pass undeflected is (Given, mass of electron $=9.1\times {10}^{-31}\mathrm{kg}$)
The susceptibility of a paramagnetic material is $99$. The permeability of the material in $\mathrm{Wb}/A-m$, is [Permeability of free space ${\mu }_{0}=4\pi \times {10}^{-7}\mathrm{Wb}/A-m$]
Two uniformly charged spherical conductors $A$ and $B$ of radii $5\mathrm{mm}$ and $10\mathrm{mm}$ are separated by a distance of $2\mathrm{cm}$. If the spheres are connected by a conducting wire, then in equilibrium condition, the ratio of the magnitudes of the electric fields at the surface of the sphere $A$ and $B$ will be
The variation of applied potential and current flowing through a given wire is shown in figure. The length of wire is $31.4\mathrm{cm}$. The diameter of wire is measured as $2.4\mathrm{cm}$. The resistivity of the given wire is measured as $x\times {10}^{-3}\Omega \mathrm{cm}$. The value of $x$ is _____ . [Take $\pi =3.14$] 
A singly ionized magnesium atom $(A=24)$ ion is accelerated to kinetic energy $5\mathrm{keV}$, and is projected perpendicularly into a magnetic field $B$ of the magnitude $0.5T$. The radius of path formed will be _____ $\mathrm{cm}.$
An AC source is connected to an inductance of $100\mathrm{mH}$, a capacitance of $100\mu F$ and a resistance of $120\Omega$ as shown in figure. The time in which the resistance having a thermal capacity $2JC-1\circ$ will get heated by $16^{\circ}C$ is _____ $s$. 
In the figure, a very large plane sheet of positive charge is shown. ${P}_{1}$ and ${P}_{2}$ are two points at distance $l$ and $2l$ from the charge distribution. If $\sigma$ is the surface charge density, then the magnitude of electric fields ${E}_{1}$ and ${E}_{2}$ at ${P}_{1}$ and ${P}_{2}$ respectively are 
What will be the most suitable combination of three resistors $A=2\Omega ,B=4\Omega ,C=6\Omega$ so that $(\frac{22}{3})\Omega$ is equivalent resistance of combination?
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 resistance of the coil is $5\mathrm{ohm}$, then the induced current through the coil at $t=2s$ will be,
The intensity of the light from a bulb incident on a surface is $0.22W{m}^{-2}$. The amplitude of the magnetic field in this light-wave is _____ $\times {10}^{-9}T$ (Given : Permittivity of vacuum ${\epsilon }_{0}=8.85\times {10}^{-12}{C}^{2}{N}^{-1}{m}^{-2}$, speed of light in vacuum $c=3\times {10}^{8}{ms}^{-1}$)
Two concentric circular loops of radii ${r}_{1}=30\mathrm{cm}$ and ${r}_{2}=50\mathrm{cm}$ are placed in $X-Y$ plane as shown in the figure. A current $I=7A$ is flowing through them in the direction as shown in figure. The net magnetic moment of this system of two circular loops is approximately 
A capacitor ${C}_{1}$ of capacitance $5\mu F$ is charged to a potential of $30V$ using a battery. The battery is then removed and the charged capacitor is connected to an uncharged capacitor ${C}_{2}$ of capacitance $10\mu F$ as shown in figure. When the switch is closed charge flows between the capacitors. At equilibrium, the charge on the capacitor ${C}_{2}$ is _____ $\mu C$. 
Given below are two statements. Statement I : Electric potential is constant within and at the surface of each conductor. Statement II : Electric field just outside a charged conductor is perpendicular to the surface of the conductor at every point. In the light of the above statements, choose the most appropriate answer from the options give below.
Magnetic flux (in weber) in a closed circuit of resistance $20\Omega$ varies with time $t(s)$ as $\phi =8{t}^{2}-9t+5$. The magnitude of the induced current at $t=0.25s$ will be _____ $\mathrm{mA}$.
Two long parallel conductors ${S}_{1}$ and ${S}_{2}$ are separated by a distance $10\mathrm{cm}$ and carrying currents of $4A$ and $2A$ respectively. The conductors are placed along $x$-axis in $X-Y$ plane. There is a point $P$ located between the conductors (as shown in figure). A charge particle of $3\pi$ coulomb is passing through the point $P$ with velocity $\vec{v}=(2\hat{i}+3\hat{j})m{s}^{-1}$; where $\hat{i}$ & $\hat{j}$ represents unit vector along $x$ & $y$axis respectively. The force acting on the charge particle is $4\pi \times {10}^{-5}(-x\hat{i}+2\hat{j})N$. The value of $x$ is 
In the given circuit, the magnitude of ${V}_{L}$ and ${V}_{C}$ are twice that of ${V}_{R}$. Given that $f=50\mathrm{Hz}$, the inductance of the coil is $\frac{1}{K\pi }\mathrm{mH}$. The value of $K$ is _____ . 
A parallel plate capacitor with plate area $A$ and plate separation $d=2m$ has a capacitance of $4\mu F$. The new capacitance of the system if half of the space between them is filled with a dielectric material of dielectric constant $K=3$ (as shown in figure) will be 
A source of potential difference $V$ is connected to the combination of two identical capacitors as shown in the figure. When key $K$ is closed, the total energy stored across the combination is ${E}_{1}$. Now key $K$ is opened and dielectric of dielectric constant $5$ is introduced between the plates of the capacitors. The total energy stored across the combination is now ${E}_{2}$. The ratio $\frac{{E}_{1}}{{E}_{2}}$ will be 
A slab of dielectric constant $K$ has the same crosssectional area as the plates of a parallel plate capacitor and thickness $\frac{3}{4}d$, where $d$ is the separation of the plates. The capacitance of the capacitor when the slab is inserted between the plates will be : (Given ${C}_{0}=$ capacitance of capacitor with air as medium between plates.)
The displacement current of $4.425\mu A$ is developed in the space between the plates of parallel plate capacitor when voltage is changing at a rate of ${10}^{6}V{s}^{-1}$. The area of each plate of the capacitor is $40{\mathrm{cm}}^{2}$. The distance between each plate of the capacitor is $x\times {10}^{-3}m$. The value of $x$ is , (Permittivity of free space, ${\epsilon }_{0}=8.85\times {10}^{-12}{C}^{2}{N}^{-1}{m}^{-2}$) _______