The induced emf cannot be produced by:

Magnetic flux passing through a coil is initially $4 \times 10^{-4} \ Wb$. It reduces to $10 \%$ of its original value in $t$ seconds. If the induced emf is $0.72 \ mV$,then $t$ in seconds is:

The charge which will flow through a galvanometer of resistance $200 \Omega$ connected to a $400 \Omega$ circular coil of $1000$ turns wound on a wooden stick $20 \ mm$ in diameter,if a magnetic field $B=0.012 \ T$ parallel to the axis of the stick is decreased suddenly to zero,is nearly: (in $\mu C$)

Three resistances of magnitude $R$ each are connected in the form of an equilateral triangle of side $a$. The combination is placed in a magnetic field $B = B_0 e^{-\lambda t}$ perpendicular to its plane. The induced current in the circuit is given by:

The north pole of a long horizontal bar magnet is being brought closer to a vertical conducting plane along the perpendicular direction. The direction of the induced current in the conducting plane will be

What will be the direction of current in the coil $A$ as the switch $S$ is closed?