JEE Main Physics — Electromagnetism previous year questions with solutions.
The magnetic flux $\phi$ (in weber) linked with a closed circuit of resistance $8\Omega$ varies with time (in seconds) as $\phi =5{t}^{2}-36t+1$. The induced current in the circuit at $t=2s$ is _______ $A$.
In the given circuit, the current in resistance ${R}_{3}$ is: 
A galvanometer has a resistance of $50\Omega$ and it allows maximum current of $5\mathrm{mA}$. It can be converted into voltmeter to measure upto $100V$ by connecting in series a resistor of resistance.
The current flowing through the $1 \Omega$ resistor is $\frac{n}{10}$ A. The value of $n$ is _________ 
A capacitor of capacitance $C$ and potential $V$ has energy $E.$ It is connected to another capacitor of capacitance $2C$ and potential $2V$. Then the loss of energy is $\frac{x}{3}E$, where $x$ is _______.
In an a.c. circuit, voltage and current are given by: $V=100\mathrm{sin}(100t)V$ and $I=100\mathrm{sin}(100t+\frac{\pi }{3})\mathrm{mA}$ respectively. The average power dissipated in one cycle is :
Electromagnetic waves travel in a medium with speed of $1.5 \times 10^8 \mathrm{~m} \mathrm{~s}^{-1}$. The relative permeability of the medium is 2.0 . The relative permittivity will be:
A moving coil galvanometer has $100$ turns and each turn has an area of $2.0{\mathrm{cm}}^{2}.$ The magnetic field produced by the magnet is $0.01T$ and the deflection in the coil is $0.05$ radian when a current of $10\mathrm{mA}$ is passed through it. The torsional constant of the suspension wire is $x\times {10}^{-5}N-m/\mathrm{rad}.$ The value of $x$ is ______ .
A rectangular loop of length $2.5m$ and width $2m$ is placed at $60^{\circ}$ to a magnetic field of $4T$. The loop is removed from the field in $10\mathrm{sec}$. The average emf induced in the loop during this time is
Two insulated circular loop $A$ and $B$ radius $a$ carrying a current of $I$ in the anti clockwise direction as shown in figure. The magnitude of the magnetic induction at the centre will be: 
Two charged conducting spheres of radii $a$ and $b$ are connected to each other by a conducting wire. The ratio of charges of the two spheres respectively is:
A series LCR circuit is subjected to an ac signal of $200 \mathrm{~V}, 50 \mathrm{~Hz}$. If the voltage across the inductor $(\mathrm{L}=10 \mathrm{mH})$ is $31.4 \mathrm{~V}$, then the current in this circuit is _____ .
A rigid wire consists of a semicircular portion of radius $R$ and two straight sections. The wire is partially immerged in a perpendicular magnetic field $B={B}_{0}\hat{j}$ as shown in figure. The magnetic force on the wire if it has a current $i$ is : 
An electric bulb rated $50 \mathrm{~W}-200 \mathrm{~V}$ is connected across a $100 \mathrm{~V}$ supply. The power dissipation of the bulb is:
A long straight wire of radius a carries a steady current I. The current is uniformly distributed across its cross section. The ratio of the magnetic field at $\frac{a}{2}$ and $2 a$ from axis of the wire is :
In an ammeter, $5%$ of the main current passes through the galvanometer. If resistance of the galvanometer is $G,$ the resistance of ammeter will be:
The current in an inductor is given by $\mathrm{I}=(3 \mathrm{t}+8)$ where $\mathrm{t}$ is in second. The magnitude of induced emf produced in the inductor is $12 \mathrm{mV}$. The self-inductance of the inductor _____ $\mathrm{mH}$.
The electric field of an electromagnetic wave in free space is represented as $\vec{E}={E}_{0}\mathrm{cos}(\omega t-kz)\hat{i}$. The corresponding magnetic induction vector will be :
A capacitor of $10 \mu \mathrm{F}$ capacitance whose plates are separated by $10 \mathrm{~mm}$ through air and each plate has area $4 \mathrm{~cm}^2$ is now filled equally with two dielectric media of $\mathrm{K}_1=2, \mathrm{~K}_2=3$ respectively as shown in figure. If new force between the plates is $8 \mathrm{~N}$. The supply voltage is _________ $\times 10^{-4} \mathrm{~V}$.  (we modified language of question to make it correct)
Two long, straight wires carry equal currents in opposite directions as shown in figure. The separation between the wires is $5.0\mathrm{cm}$. The magnitude of the magnetic field at a point $P$ midway between the wires is $_____\mu T$. (Given: ${\mu }_{0}=4\pi \times {10}^{-7}Tm{A}^{-1}$) 
A parallel plate capacitor has a capacitance $C=200\mathrm{pF}$. It is connected to $230V$ ac supply with an angular frequency $300\mathrm{rad}{s}^{-1}$. The rms value of conduction current in the circuit and displacement current in the capacitor respectively are :
In a coil, the current changes from $-2 \mathrm{~A}$ to $+2 \mathrm{~A}$ in $0.2 \mathrm{~s}$ and induces an emf of $0.1 \mathrm{~V}$. The self inductance of the coil is :
Two parallel long current carrying wire separated by a distance $2 r$ are shown in the figure. The ratio of magnetic field at $A$ to the magnetic field produced at $C$ is $\frac{x}{7}$. The value of $x$ is _____ 
A plane electromagnetic wave propagating in $x$-direction is described by ${E}_{y}=(200V{m}^{-1})\mathrm{sin}[1.5\times {10}^{7}t-0.05x];$The intensity of the wave is : (Use ${\epsilon }_{0}=8.85\times {10}^{-12}{C}^{2}{N}^{-1}{m}^{-2}$)