$A$ 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 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 (in seconds): (in $s$)

The magnetic flux through a coil is $4 \times 10^{-4} \ Wb$ at time $t=0$. It reduces to $30 \%$ of its original value in time $t$ seconds. If the e.m.f. induced in the coil is $0.56 \ mV$,then the value of $t$ is: (in $s$)

$A$ coil has $200$ turns and an area of $70 \ cm^2$. The magnetic field perpendicular to the plane of the coil is $0.3 \ Wb/m^2$ and it takes $0.1 \ s$ to rotate through $180^o$. The value of the induced $e.m.f.$ will be ...... $V$.

$A$ uniform magnetic field is restricted within a region of radius $r$. The magnetic field changes with time at a rate $\frac{d\vec{B}}{dt}$. Loop $1$ of radius $R > r$ encloses the region,and loop $2$ of radius $R$ is outside the region of the magnetic field as shown in the figure. Then the $e.m.f.$ generated is:

$A$ long solenoid of radius $2\, cm$ has $100\, turns/cm$ and carries a current of $5\, A$. $A$ coil of radius $1\, cm$ having $100\, turns$ and a total resistance of $20\, \Omega$ is placed inside the solenoid coaxially. The coil is connected to a galvanometer. If the current in the solenoid is reversed in direction,find the charge flown through the galvanometer.

$A$ coil of resistance $250 \Omega$ is placed in a magnetic field. If the magnetic flux $(\phi)$ linked with the coil varies with time $t$ $(s)$ as $\phi = 50t^2 + 7$,the current in the coil at $t = 4 \ s$ is: (in $A$)