Electromagnetism PYQ — Page 3

In the circuit shown below, the inductance $L$ is connected to an ac source. The current flowing in the circuit is $I=I_0 \sin \omega t$. The voltage drop $\left(V_L\right)$ across $L$ is 

In the following circuit, the equivalent capacitance between terminal $A$ and terminal $B$ is : 

Match List-I with List-II. $\begin{array}{ll|rl} & \text{List-I} & & \begin{array}{l} \text{List-II} \\ \text{(Susceptibility } (\chi))\end{array} \\ \hline A. & \text{Diamagnetic} & I. & \chi=0 \\ B. & \text{Ferromagnetic} & II. & 0 \gt \chi \geq-1 \\ C. & \text{Paramagnetic} & III. & \chi \gt \gt 1 \\ D. & \text{Non-magnetic} & IV. & 0 \lt \chi \lt \varepsilon \text{(a small positive number)} \end{array}$ Choose the correct answer from the options given below

The magnetic moment of an iron bar is $M$. It is now bent in such a way that it forms an arc section of a circle subtending an angle of $60^{\circ}$ at the centre. The magnetic moment of this arc section is

A thin spherical shell is charged by some source. The potential difference between the two points $C$ and $P$ (in V ) shown in the figure is: (Take $\frac{1}{4 \pi \varepsilon_0}=9 \times 10^9$ SI units) 

An electric dipole is placed at an angle of $30^{\circ}$ with an electric field of intensity $2\times {10}^{5}N{C}^{-1}$. It experiences a torque equal to $4Nm$. Calculate the magnitude of charge on the dipole, if the dipole length is $2\mathrm{cm}$.

A $12V,60W$ lamp is connected to the secondary of a step down transformer, whose primary is connected to ac mains of $220V$. Assuming the transformer to be ideal, what is the current in the primary winding?

An electric dipole is placed as shown in the figure.  The electric potential (in ${10}^{2}V$) at point $P$ due to the dipole is (${\epsilon }_{0}$=permittivity of free space and $\frac{1}{4\pi {\epsilon }_{0}}=K$)

The electric field inside a conductor is

If $Z_1$ and $Z_2$ are the impedances of the given circuits (a) and (b) as shown in figures, then choose the correct option. 

For very high frequencies, the effective impedance of the circuit (shown in the figure) will be 

In a series$LCR$ circuit, the inductance$L$ is $10\mathrm{mH}$, capacitance $C$ is $1\mu F$ and resistance $R$ is $100\Omega$. The frequency at which resonance occurs is:

A uniform electric field and a uniform magnetic field are acting along the same direction in a certain region. If an electron is projected in the region such that its velocity is pointed along the direction of fields, then the electron

The net impedance of circuit (as shown in figure) will be: 

A very long conducting wire is bent in a semi- circular shape from $A$ to $B$ as shown in figure. The magnetic field at point$P$ for steady current configuration is given by: 

The net magnetic flux through any closed surface is:

On the basis of electrical conductivity, which one of the following material has the smallest resistivity?

The resistance of platinum wire at $0^{\circ}C$ is $2\Omega$ and $6.8\Omega$ at $80^{\circ}C$. The temperature coefficient of resistance of the wire is:

An emf is generated by an ac generator having 100 turn coil, of loop area $1 \mathrm{~m}^2$. The coil rotates at a speed of one revolution per second and placed in a uniform magnetic field of $0.05 \mathrm{~T}$ perpendicular to the axis of rotation of the coil. The maximum value of emf is

To produce an instantaneous displacement current of $2 \mathrm{~mA}$ in the space between the parallel plates of a capacitor of capacitance $4 \mu \mathrm{F}$, the rate of change of applied variable potential difference $\left(\frac{d V}{d t}\right)$ must be

$10$ resistors, each of resistance $R$ are connected in series to a battery of emf $E$ and negligible internal resistance. Then those are connected in parallel to the same battery, the current is increased $n$ times. The value of $n$ is:

If $\underset{S}{\oint }\vec{E}\cdot d\vec{S}=0$ over a surface, then:

A wire carrying a current $I$ along the positive x-axis has length $L$. It is kept in a magnetic field $\vec{B}=(2\hat{i}+3\hat{j}-4\hat{k})T$. The magnitude of the magnetic force acting on the wire is:

If a conducting sphere of radius $R$ is charged. Then the electric field at a distance $r(r>R)$ from the centre of the sphere would be, $(V=$ potential on the surface of the sphere $)$