The magnetic flux through a coil of resistance $10\,\Omega$ is changed by $\Delta \phi$ in $0.1\,s$. The resulting current in the coil varies with time as shown in the figure. Then,the magnitude $\left| \Delta \phi \right|$ is equal to (in weber):

$A$ magnetic field $4 \times 10^{-2} \, T$ acts at right angles to a coil of area $100 \, cm^2$ with $50$ turns. The average e.m.f. induced in the coil is $0.1 \, V$, when it is removed from the field in time '$t$'. The value of '$t$' is

$A$ coil of circular cross-section having $1000$ turns and $4 \, cm^2$ face area is placed with its axis parallel to a magnetic field which decreases by $10^{-2} \, Wb \, m^{-2}$ in $0.01 \, s$. The $e.m.f.$ induced in the coil is....$mV$

$A$ magnetic field of $2 \times 10^{-2} \, T$ acts at right angles to a coil of area $100 \, cm^2$ with $50$ turns. The average emf induced in the coil is $0.1 \, V$,when it is removed from the field in time $t$. The value of $t$ is $... \, sec$.

$A$ coil of effective area $3 \text{ m}^2$ is placed at right angles to a magnetic field of induction $0.05 \text{ Wb/m}^2$. If the field is decreased to $20\%$ of its original value in $10 \text{ seconds}$, the e.m.f. induced in the coil will be (in $\text{ mV}$)

The figure shows the north pole of a magnet moving away from a thick conducting loop containing a capacitor. The excess positive charge will arrive on