The magnetic flux linked with a closed coil is increased to a maximum value in $2 \,s$ and its relation with time is $\phi = at^2 + bt + c$. Then the relation between $a, b$ and $c$ is:

In which of the following systems of units is $Weber$ the unit of magnetic flux?

Calculate the magnetic flux through the triangular loop shown in the figure. $A$ uniform magnetic field of strength $2 \text{ T}$ points perpendicularly into the plane of the triangle.

Write Gauss's law for magnetism.

$A$ circular loop of radius $R$ carrying current $I$ lies in the $x-y$ plane with its centre at the origin. The total magnetic flux through the $x-y$ plane is:

$A$ loop $ABCDEFA$ of straight edges has six corner points $A(0,0,0), B(5,0,0), C(5,5,0), D(0,5,0), E(0,5,5)$ and $F(0,0,5)$. The magnetic field in this region is $\overrightarrow{B}=(3 \hat{i}+4 \hat{k}) \; T$. The quantity of magnetic flux through the loop $ABCDEFA$ (in $\text{Wb}$) is: