NEET UG 2023 — Electromagnetism

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 $)$

The magnitude and direction of the current in the following circuit is 

A copper wire of radius $1 \mathrm{~mm}$ contains $10^{22}$ free electrons per cubic metre. The drift velocity for free electrons when $10 \mathrm{~A}$ current flows through the wire will be (Given, charge on electron $=1.6 \times 10^{-19} \mathrm{C}$ )

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

An ac source is connected to a capacitor $C$. Due to decrease in its operating frequency:

The equivalent capacitance of the arrangement shown in figure is 

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

An ac source is connected in the given circuit. The value of $\phi$ will be 

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)

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

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

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 =$3\times {10}^{8}m{s}^{-1}$)

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 $\left(g=9.8 \mathrm{~ms}^{-2}\right)$

The magnetic energy stored in an inductor of inductance $4\mu H$ carrying a current of $2A$ is:

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

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 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 $2\mathrm{cm}$.