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):

$A$ coil having $500$ square loops each of side $10 \ cm$ is placed normal to a magnetic flux which increases at a rate of $1 \ T s^{-1}$. The induced emf is (in $V$)

The coil of area $0.1 \ m^2$ has $500$ turns. After placing the coil in a magnetic field of strength $4 \times 10^{-4} \ Wb/m^2$,if it is rotated through $90^o$ in $0.1 \ s$,the average emf induced in the coil is......$V$

$A$ rectangular coil of $100$ turns and size $0.1 \,m \times 0.05 \,m$ is placed perpendicular to a magnetic field of $0.1 \,T$. If the field drops to $0.05 \,T$ in $0.05 \,s$, the magnitude of the e.m.f. induced in the coil is (in $\,V$)

$A$ circular coil has $100$ turns,radius $3 \ cm$ and resistance $4 \Omega$. This coil is co-axial with a solenoid of $200$ turns/cm and diameter $4 \ cm$. If the solenoid current is decreased from $2 \ A$ to zero in $0.04 \ s$,then the current induced in the coil is

Magnetic flux linked with a coil is $\phi = 5t^2 + 2t + 3$,where $t$ is in seconds and $\phi$ is in webers. At time $t = 1 \ s$,the value of the induced emf is . . . . . . $V$.