Electromagnetism PYQ — Page 4

A charge $Q \mu C$ is placed at the centre of a cube. The flux coming out from any one of its faces will be (in SI unit)

The electric field inside a conductor is

If the galvanometer $G$ does not show any deflection in the circuit shown, the value of $R$ is given by: 

According to Gauss law of electrostatics, electric flux through a closed surface depends on

The emf of a cell having internal resistance $1 \Omega$ is balanced against a length of $330 \mathrm{~cm}$ on a potentiometer wire. When an external resistance of $2 \Omega$ is connected across the cell, the balancing length will be

The equivalent capacitance of the system shown in the following circuit is: 

A long straight wire of length $2 \mathrm{~m}$ and mass $250 \mathrm{~g}$ is suspended horizontally in a uniform horizontal magnetic field of $0.7 \mathrm{~T}$. The amount of current flowing through the wire will be $\left(g=9.8 \mathrm{~ms}^{-2}\right)$

A certain wire $A$ has resistance $81 \Omega$. The resistance of another wire $B$ of same material and equal length but of diameter thrice the diameter of $A$ will be

The maximum power is dissipated for an ac in a/an

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

The variation of susceptibility $(\chi)$ with absolute temperature $(T)$ for a paramagnetic material is represented as:

The equivalent capacitance of the arrangement shown in figure is 

In a plane electromagnetic wave travelling in free space, the electric field component oscillates sinusoidally at a frequency of $2.0\times {10}^{10}\mathrm{Hz}$ and amplitude $48V{m}^{-1}$. Then the amplitude of oscillating magnetic field is: (Speed of light in free space =$3\times {10}^{8}m{s}^{-1}$)

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 $\frac{1}{4\pi {\epsilon }_{0}}=K$)

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 $2\mathrm{cm}$.

As the temperature increases, the electrical resistance

The unit of electric potential is

The magnetic field of a plane electromagnetic wave is given by $\overrightarrow{\mathrm{B}}=3 \times 10^{-8} \cos \left(1.6 \times 10^3 x+\right.$ $48 \times 10^{10}$ t) $\hat{j}$, then the associated electric field will be:

A capacitor of capacitance $C=900\mathrm{pF}$ is charged fully by $100V$ battery $B$ as shown in figure (a). Then it is disconnected from the battery and connected to another uncharged capacitor of capacitance $C=900\mathrm{pF}$ as shown in figure (b). The electrostatic energy stored by the system (b) is 

The equivalent resistance of the infinite network given below is: 

An inductor of inductance $2 \mathrm{mH}$ is connected to a $220 \mathrm{~V}, 50 \mathrm{~Hz}$ a.c. source. Let inductive reactance in the circuit is $X_1$. If a $220 \mathrm{~V}$ d.c. source replaces the a.c. source in the circuit, then the inductive reactance in the circuit is $\mathrm{X}_2 \cdot \mathrm{X}_1$ and $\mathrm{X}_2$ respectively are:

The magnetic field on the axis of a circular loop of radius $100 \mathrm{~cm}$ carrying current $I=\sqrt{2} \mathrm{~A}$, at point $1 \mathrm{~m}$ away from the centre of the loop is given by:

The ratio of coulomb's electrostatic force to the gravitational force between an electron and a proton separated by some distance is $2.4 \times 10^{39}$. The ratio of the proportionality constant, $\mathrm{K}=$ $\frac{1}{4 \pi \varepsilon_0}$ to the Gravitational constant G is nearly (Given that the charge of the proton and electron each $=1.6 \times 10^{-19} \mathrm{C}$, the mass of the electron $=9.11 \times 10^{-31} \mathrm{~kg}$, the mass of the proton $=$ $\left.1.67 \times 10^{-27} \mathrm{~kg}\right)$