JEE Main Physics — Electromagnetism previous year questions with solutions.
An LCR series circuit of capacitance $62.5\mathrm{nF}$ and resistance of $50\Omega$, is connected to an A.C. source of frequency $2.0\mathrm{kHz}$. For maximum value of amplitude of current in circuit, the value of inductance is ____$\mathrm{mH}$.$(\text{Take}{\pi }^{2}=10)$
Given below are two statements: Statement I : Out of microwaves, infrared rays and ultraviolet rays, ultraviolet rays are the most effective for the emission of electrons from a metallic surface Statement II : Above the threshold frequency, the maximum kinetic energy of photoelectrons is inversely proportional to the frequency of the incident light In the light of above statements, choose the correct answer from the options given below
A coil has an inductance of $2H$ and resistance of $4\Omega$. A $10V$ is applied across the coil. The energy stored in the magnetic field after the current has built up to its equilibrium value will be _____ $\times {10}^{-2}J$
For the plane electromagnetic wave given by $E={E}_{0}\mathrm{sin}(\omega t–kx)$ and $B={B}_{0}\mathrm{sin}(\omega t-kx),$ the ratio of average electric energy density to average magnetic energy density is
The magnitude of magnetic induction at mid-point $O$ due to current arrangement as shown in figure will be .
A potential ${V}_{0}$ is applied across a uniform wire of resistance $R.$ The power dissipation is ${P}_{1}.$ The wire is then cut into two equal halves and a potential of ${V}_{0}$ is applied across the length of each half. The total power dissipation across two wires is ${P}_{2}.$ The ratio of ${P}_{2}:{P}_{1}$ is $\sqrt{x}:1.$ The value of $x$ is _____.
Given below are two statements: Statement I: For diamagnetic substance $-1\leq x<0$, where $x$ is the magnetic susceptibility. Statement II: Diamagnetic substance when placed in an external magnetic field, tend to move from stronger to weaker part of the field. In the light of the above statements, choose the correct answer from the options give below.
A rectangular parallelopiped is measured as $1\mathrm{cm}\times 1\mathrm{cm}\times 100\mathrm{cm}$. If its specific resistance is $3\times {10}^{-7}\Omega m$, then the resistance between its two opposite rectangular faces will be _____$\times {10}^{-7}\Omega$. 
A charge particle of $2\mu C$ accelerated by a potential difference of $100V$ enters a region of uniform magnetic field of magnitude $4\mathrm{mT}$ at right angle to the direction of field. The charge particle completes semicircle of radius $3\mathrm{cm}$ inside magnetic field. The mass of the charge particle is ______ $\times {10}^{-18}\mathrm{kg}$.
A parallel plate capacitor of capacitance $2F$ is charged to a potential $V$. The energy stored in the capacitor is ${E}_{1}$. The capacitor is now connected to another uncharged identical capacitor in parallel combination. The energy stored in the combination is ${E}_{2}$. The ratio $\frac{{E}_{2}}{{E}_{1}}$ is
As shown in the figure the voltmeter reads $2V$ across $5\Omega$ resistor. The resistance of the voltmeter is _____ $\Omega$ 
In an electromagnetic wave, at an instant and at a particular position, the electric field is along the negative z-axis and magnetic field is along the positive x-axis. Then the direction of propagation of electromagnetic wave is:
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 end of rod as shown in figure. The induced emf will be : .
The electric current in a circular coil of four turns produces a magnetic induction $32T$ at its centre. The coil is unwound and is rewound into a circular coil of single turn, the magnetic induction at the centre of the coil by the same current will be :
A capacitor of capacitance $900\mu F$ is charged by a $100V$ battery. The capacitor is disconnected from the battery and connected to another uncharged identical capacitor such that one plate of uncharged capacitor connected to positive plate and another plate of uncharged capacitor connected to negative plate of the charged capacitor. The loss of energy in this process is measured as $x\times {10}^{-2}J$. The value of $x$ is ______.
Two long current carrying conductors are placed parallel to each other at a distance of $8\mathrm{cm}$ between them. The magnitude of magnetic field produced at mid-point between the two conductors due to current flowing in them is $300\mu T$. The equal current flowing in the two conductors is :
A long straight wire with a circular cross-section having radius $R$, is carrying a steady current $I$. The current $I$ is uniformly distributed across this cross-section. Then the variation of magnetic field due to current $I$ with distance $r(r<R)$ from its centre will be
If $n$ represents the actual number of deflections in a converted galvanometer of resistance $G$ and shunt resistance $S$. Then the total current $I$ when its figure of merit is $K$ will be
A transformer operating at primary voltage $8\mathrm{kV}$ and secondary voltage $160V$ serves a load of $80\mathrm{kW}$. Assuming the transformer to be ideal with purely resistive load and working on unity power factor, the loads in the primary and secondary circuit would be
A deuteron and a proton moving with equal kinetic energy enter into to a uniform magnetic field at right angle to the field. If ${r}_{d}$ and ${r}_{p}$ are the radii of their circular paths respectively, then the ratio $\frac{{r}_{d}}{{r}_{p}}$ will be $\sqrt{x}:1$ where $x$ is _____ .
A current of $15\mathrm{mA}$ flows in the circuit as shown in figure. The value of potential difference between the points $A$ and $B$ will be 
A composite parallel plate capacitor is made up of two different dielectric materials with different thickness (${t}_{1}$ and ${t}_{2}$) as shown in figure. The two different dielectric material are separated by a conducting foil $F$. The voltage of the conducting foil is _____ $V$. 
Find the equivalent resistance between point $A$ and $B$ 
$27$ identical drops are charged at $22V$ each. They combine to form a bigger drop. The potential of the bigger drop will be _____ $V$.