List of top Physics Questions on Magnetism and Maxwell's Equations asked in IIT JAM PH

A time dependent magnetic field inside a long solenoid of radius 0.05m is given by $\overrightarrow𝐵$(𝑡) = 𝐵₀ sin 𝜔𝑡 $\^z$. If 𝜔=100rad/s and 𝐵₀= 0.98Weber/m² , then the amplitude of the induced electric field at a distance of 0.07m from the axis of the solenoid is ______V/m. (Rounded off to two decimal places)

A 15.7mW laser beam has a diameter of 4mm. If the amplitude of the associated magnetic field is expressed as $\frac{𝐴}{\sqrt{ε_0𝑐^3}}$ , the value of A is: (𝜀₀ is the free space permittivity and 𝑐 is the speed of light)

The magnitudes of spin magnetic moments of electron, proton and neutron are μ_e, μ_p and μ_n, respectively. Then

A small bar magnet is dropped through different hollow copper tubes with same length and inner diameter but with different outer diameter. The variation in the time (t) taken for the magnet to reach the bottom of the tube depends on its wall thickness (d) as

Suppose the divergence of magnetic field $\vec{𝐵}$ is nonzero and is given as $∇⃗.\vec{𝐵} = \mu_0\rho_m$, where 𝜇₀ is the permeability of vacuum and 𝜌_m is the magnetic charge density. If the corresponding magnetic current density is $\vec{J}_𝑚$, then the curl $∇⃗ × \vec{𝐸}$ of the electric field $\vec{𝐸}$ is

Consider a conical region of height h and base radius R with its vertex at the origin. Let the outward normal to its base be along the positive z-axis, as shown in the figure. A uniform magnetic field, $\overrightarrow{B}=B_0\hat{z}$ exists everywhere. Then the magnetic flux through the base ($\Phi_b$) and that through the curved surface of the cone ($\Phi_c$) are

A uniform magnetic field $\overrightarrow{B}=B_0\hat{z}$, where $B_0\gt0$ exists as shown in the figure. A charged particle of mass m and charge $q(q\gt0)$ is released at the origin, in the yz-plane, with a velocity $\overrightarrow v$ directed at an angle $\theta$= 45° with respect to the positive z-axis. Ignoring gravity, which one of the following is TRUE.

A circular loop of wire with radius R is centered at the origin of the xy-plane. The magnetic field at a point within the loop is, $\overrightarrow B(\rho,\phi,z,t)=k\rho^3t^3\hat{z}$, where k is a positive constant of appropriate dimensions. Neglecting the effects of any current induced in the loop, the magnitude of the induced emf in the loop at time t is

The magnetic fields in tesla in the two regions separated by the $z = 0$ plane are given by $\vec{B_1} = 3\hat{i} + 5\hat{j}$ and $\vec{B_2} = 8\hat{i} + 3\hat{j} + 5\hat{k}$. The magnitude of the surface current density at the interface between the two regions is $\alpha \times 10^6\, \text{A/m}$. Given the permeability of free space $\mu_0 = 4\pi \times 10^{-7}\, \text{N/A}^2$, the value of $\alpha$ is ............... . (Round off to 2 decimal places)

For electric and magnetic fields, $\vec{E}$ and $\vec{B}$, due to a charge density $\rho(\vec{r},t)$ and a current density $\vec{J}(\vec{r},t)$, which of the following relations is/are always correct?

Consider an annular region in free space containing a uniform magnetic field in the $z$-direction, schematically represented by the shaded region in the figure. A particle having charge $Q$ and mass $M$ starts from point $P(a, 0, 0)$ in the $+x$-direction with constant speed $v$. If the radii of inner and outer circles are $a$ and $b$, respectively, the minimum magnetic field required so that the particle returns to the inner circle is:

Which one of the following is an impossible magnetic field $\vec{B}$?

An infinitely long solenoid, with its axis along $\hat{k}$, carries a current $I$. In addition, there is a uniform line charge density $\lambda$ along the axis. If $\vec{S}$ is the energy flux, in cylindrical coordinates $(\hat{\rho}, \hat{\phi}, \hat{k})$, then

A long solenoid is carrying a time dependent current such that the magnetic field inside has the form $\vec{B}(t)=B_0 t^2 \hat{k}$, where $\hat{k}$ is along the axis of the solenoid. The displacement current at the point $P$ on a circle of radius $r$ in a plane perpendicular to the axis

Consider an electromagnetic plane wave $\vec{E}=E_0(\hat{t}+b\hat{y})\cos\left[\frac{2\pi}{\lambda}(ct-(x-\sqrt{3}y))\right]$, where $\lambda$ is the wavelength and $c$ is the speed of light. The value of $b$ is ............. (Specify answer up to two digits after the decimal point.)

A current $I$ flows through the sides of an equilateral triangle of side $a$. The magnetic field at the centroid is

Consider a thin long insulator coated conducting wire carrying current $ I $. It is now wound once around an insulating thin disc of radius $ R $ to bring the wire back on the same side, as shown in the figure. The magnetic field at the center of the disc is equal to:

Consider a circular parallel plate capacitor of radius $ R $ with separation $ d $ between the plates ($ d \ll R $). The plates are placed symmetrically about the origin. If a sinusoidal voltage $ V = V_0 \sin(\omega t) $ is applied between the plates, which of the following statement(s) is (are) true?