$A$ 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

$A$ magnet is moved in the direction indicated by an arrow between two coils $AB$ and $CD$ as shown in the figure. The direction of the induced current in the coils is

$A$ 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)

Assertion $(A)$: When a circular coil,placed in a region with its plane parallel to a magnetic field,expands radially outwards,no emf is induced in it.
Reason $(R)$: There is a constant magnetic field in the perpendicular (to the plane of the coil) direction.

$A$ coil is placed perpendicular to a magnetic field of $5000 \,T$. When the field is changed to $3000 \,T$ in $2 \,s$, an induced emf of $22 \,V$ is produced in the coil. If the diameter of the coil is $0.02 \,m$, then the number of turns in the coil is:

As shown in the figure,a magnet is moved with a fast speed towards a coil at rest. Due to this,the induced electromotive force,induced current,and induced charge in the coil are $E$,$I$,and $Q$ respectively. If the speed of the magnet is doubled,which of the following statements is incorrect?