The unit of magnetic flux is

The net magnetic flux through any closed surface is

Assertion $(A)$: When the plane of the coil is perpendicular to the magnetic field,the magnetic flux linked with the coil is minimum,but the induced emf is zero.
Reason $(R)$: $\phi = nAB \cos \theta$ and $e = -\frac{d\phi}{dt}$.

The magnetic flux linked with a coil of $N$ turns of area of cross section $A$ held with its plane parallel to the field $B$ is

The magnetic flux linked with a vector area $\overrightarrow{A}$ in a uniform magnetic field $\overrightarrow{B}$ is

$A$ square of side $L$ metre lies in the $x-y$ plane in a region where the magnetic field is $\vec{B} = B_0(2 \hat{i} + 3 \hat{j} + 4 \hat{k})$,where $B_0$ is a constant. The magnitude of the magnetic flux passing through the square (in weber) is: (in $B_0 L^2$)