Two identical circular loops of metal wire are lying on a table without touching each other. Loop $A$ carries a current which increases with time. In response,the loop $B$:

$A$ vertical bar magnet is dropped from the shown position on the axis of a fixed metallic coil as shown in Fig-$I$. In Fig-$II$,the magnet is fixed and a horizontal coil is dropped. If the acceleration of the magnet and coil are $a_1$ and $a_2$ respectively,then:

$A$ copper ring having a cut such as not to form a complete loop is held horizontally and a bar magnet is dropped through the ring with its length along the axis of the ring as shown in figure. The acceleration of the falling magnet is ($g=$ acceleration due to gravity)

The working of a dynamo is based on the principle of

The magnetic flux linked with a coil (in $Wb$) is given by the equation $\phi = 5t^2 + 3t + 16$. The magnitude of induced emf in the coil at the fourth second will be (in $V$):

$A$ square loop of side $10 \ cm$ and resistance $0.5 \ \Omega$ is placed vertically in the east-west plane. $A$ uniform magnetic field of $0.10 \ T$ is set across the plane in the north-east direction. The magnetic field decreases to zero at $0.70 \ s$ at a steady rate. Then the magnitude of the induced current during this time interval will be . . . . . . .