JEE Main Physics — Electromagnetism previous year questions with solutions.
The magnetic field at the centre of a circular coil of radius $r$, due to current I flowing through it, is $B$. The magnetic field at a point along the axis at a distance $\frac{r}{2}$ from the centre is :
Statement-I : A point charge is brought in an electric field. The value of electric field at a point near to the charge may increase if the charge is positive. Statement-II : An electric dipole is placed in a uniform electric field. The net electric force on the dipole will not be zero.
The current density in a cylindrical wire of radius $4\mathrm{mm}$ is $4\times {10}^{6}A{m}^{-2}$. The current through the outer portion of the wire between radial distances $\frac{R}{2}$ and $R$ is _____ $\pi A$.
Match 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>Ultravoilet rays</td><td>(i)</td><td>Study crystal structure</td></tr><tr><td>(b)</td><td>Microwaves</td><td>(ii)</td><td>Greenhouse effect</td></tr><tr><td>(c)</td><td>Infrared waves</td><td>(iii)</td><td>Sterilizing surgical instrument</td></tr><tr><td>(d)</td><td>$X$-rays</td><td>(iv)</td><td>Radar system</td></tr></tbody></table>
Two capacitors having capacitance ${C}_{1}$ and ${C}_{2}$ respectively are connected as shown in figure. Initially, capacitor ${C}_{1}$ is charged to a potential difference $V$ volt by a battery. The battery is then removed and the charged capacitor ${C}_{1}$ is now connected to uncharged capacitor ${C}_{2}$ by closing the switch $S$. The amount of charge on the capacitor ${C}_{2}$, after equilibrium, is 
The current density in a cylindrical wire of radius $r=4.0\mathrm{mm}$ is $1.0\times {10}^{6}{A}^{2}{m}^{2}$. The current through the outer portion of the wire between radial distances $\frac{r}{2}$ and $r$ is $x\pi A$; where $x$ is
Three point charges of magnitude $5\mu C,0.16\mu C$ and $0.3\mu C$ are located at the vertices $A,B,C$ of a right angled triangle whose sides are $AB=3\mathrm{cm}$, $BC=3\sqrt{2}\mathrm{cm}$ and $CA=3\mathrm{cm}$ and point $A$ is the right angle corner. Charge at point $A$ experiences _____ $N$ of electrostatic force due to the other two charges.
An EM wave propagating in $x$-direction has a wavelength of $8\mathrm{mm}$. The electric field vibrating $y$-direction has maximum magnitude of $60{\mathrm{Vm}}^{-1}$. Choose the correct equations for electric and magnetic fields if the EM wave is propagating in vacuum :
Two coils require $20$ minutes and $60$ minutes respectively to produce same amount of heat energy when connected separately to the same source. If they are connected in parallel arrangement to the same source; the time required to produce same amount of heat by the combination of coils, will be _____ $\mathrm{min}$.
Given below are two statements : Statement - I : Susceptibilities of paramagnetic and ferromagnetic substances increase with decrease in temperature. Statement - II : Diamagnetism is a result of orbital motions of electrons developing magnetic moments opposite to the applied magnetic field. Choose the correct answer from the options given below
For the network shown below, the value of ${V}_{B}-{V}_{A}$ is _____ $V$. 
The total current supplied to the circuit as shown in figure by the $5V$ battery is _____ $A$. 
Given below are two statements : Statement I : A uniform wire of resistance $80\Omega$ is cut into four equal parts. These parts are now connected in parallel. The equivalent resistance of the combination will be $5\Omega$. Statement II : Two resistance $2R$ and $3R$ are connected in parallel in an electric circuit. The value of thermal energy developed in $3R$ and $2R$ will be in the ratio $3:2$. In the light of the above statements, choose the most appropriate answer from the options given below
A parallel plate capacitor is formed by two plates each of area $30\pi {\mathrm{cm}}^{2}$ separated by $1\mathrm{mm}$. A material of dielectric strength $3.6\times {10}^{7}V{m}^{-1}$ is filled between the plates. If the maximum charge that can be stored on the capacitor without causing any dielectric breakdown is $7\times {10}^{-6}C$, the value of dielectric constant of the material is : [Use $\frac{1}{4\pi {\epsilon }_{o}}=9\times {10}^{9}N{m}^{2}{C}^{-2}$]
A beam of light travelling along $X$-axis is described by the electric field ${E}_{y}=900\mathrm{sin}\omega (t-\frac{x}{c})$. The ratio of electric force to magnetic force on a charge $q$ moving along $Y$-axis with a speed of $3\times {10}^{7}m{s}^{-1}$ will be : [Given speed of light $=3\times {10}^{8}m{s}^{-1}$ ]
A. The drift velocity of electrons decreases with the increase in the temperature of conductor. B. The drift velocity is inversely proportional to the area of cross-section of given conductor. C. The drift velocity does not depend on the applied potential difference to the conductor. D. The drift velocity of electron is inversely proportional to the length of the conductor. E. The drift velocity increases with the increase in the temperature of conductor. Choose the correct answer from the options given below:
A parallel plate capacitor with width $4\mathrm{cm}$, length $8\mathrm{cm}$ and separation between the plates of $4\mathrm{mm}$ is connected to a battery of $20V$. A dielectric slab of dielectric constant $5$ having length $1\mathrm{cm}$, width $4\mathrm{cm}$ and thickness $4\mathrm{mm}$ is inserted between the plates of parallel plate capacitor. The electrostatic energy of this system will be _____ ${\epsilon }_{0}J$. (Where ${\epsilon }_{0}$ is the permittivity of free space)
To increase the resonant frequency in series LCR circuit,
Two bar magnets oscillate in a horizontal plane in earth's magnetic field with time periods of $3s$ and $4s$respectively. If their moments of inertia are in the ratio of $3:2$ then the ratio of their magnetic moments will be
Two charged particles, having same kinetic energy, are allowed to pass through a uniform magnetic field perpendicular to the direction of motion. If the ratio of radii of their circular paths is $6:5$ and their respective masses ratio is $9:4$. Then, the ratio of their charges will be
Three identical charged balls each of charge $2C$ are suspended from a common point $P$ by silk threads of $2m$ each (as shown in figure). They form an equilateral triangle of side $1m$. The ratio of net force on a charged ball to the force between any two charged balls will be 
When you walk through a metal detector carrying a metal object in your pocket, it raises an alarm. This phenomenon works on
A spherically symmetric charge distribution is considered with charge density varying as $\rho (r)={\begin{matrix}{\rho }_{0}(\frac{3}{4}-\frac{r}{R}) & \text{ for }r\leq R \\ \mathrm{Zero} & & & \mathrm{for}r>R\end{matrix}$ Where, $r(r<R)$ is the distance from the centre $O$ (as shown in figure). The electric field at point $P$ will be : 
Two coils of self inductance ${L}_{1}$ and ${L}_{2}$ are connected in series combination having mutual inductance of the coils as $M$. The equivalent self inductance of the combination will be 