A certain elastic conducting material is stretched into a circular loop. It is placed with its plane perpendicular to a uniform magnetic field $B=0.8 \mathrm{T}$. When released the radius of the loop starts shrinking at a constant rate of $2 \mathrm{cm} {\mathrm{s}}^{–1}$. The induced emf in the loop at an instant when the radius of the loop is $10 \mathrm{cm}$ will be ______ $\mathrm{mV}$.

For the given figures, choose the correct options:

An inductor of inductance $2 \mathrm{\mu H}$ is connected in series with a resistance, a variable capacitor and an AC source of frequency $7 \mathrm{kHz}$. The value of capacitance for which maximum current is drawn into the circuit is $\frac{1}{x} \mathrm{F}$, where the value of $x$ is ______.

(Take $\pi \mathit{=}\frac{\mathit{22}}{\mathit{7}}$)

As per the given figure, if $\frac{\mathrm{d}I}{\mathrm{d}t}=-1 \mathrm{A} {\mathrm{s}}^{-1}$, then the value of $V_{\mathrm{AB}}$ at this instant will be ______ $\mathrm{V}$.

In the given circuit, $rms$ value of current $\left(I_{rms}\right)$ through the resistor $R$ is :

In an ac generator, a rectangular coil of $100$ turns each having area $14\times {10}^{–2} {\mathrm{m}}^2$ is rotated at $360 \mathrm{rev} {\min }^{-1}$ about an axis perpendicular to a uniform magnetic field of magnitude $3.0 \mathrm{T}$. The maximum value of the emf produced will be ______ $\mathrm{V}$.

[Take $\mathrm{\pi }=\frac{22}{7}$]

Spherical insulating ball and a spherical metallic ball of same size and mass are dropped from the same height. Choose the correct statement out of the following {Assume negligible air friction}