The figure shows the electric field lines of four point charges $A$,$B$,$C$,and $D$. Which charge has the maximum magnitude?

Electric field in a region is given by $\overrightarrow{E} = a \hat{i} + b \hat{j}$,where $a$ and $b$ are constants. The net flux passing through a square area of side $l$ parallel to the $y-z$ plane is

$A$ rectangular surface of sides $10 \,cm$ and $15 \,cm$ is placed inside a uniform electric field of $25 \,V/m$,such that the surface makes an angle of $30^{\circ}$ with the direction of the electric field. Find the flux of the electric field through the rectangular surface in $Nm^2/C$.

Electric field lines of force of a positive point charge are

The flat base of a hemisphere of radius $a$ with no charge inside it lies in a horizontal plane. $A$ uniform electric field $\vec{E}$ is applied at an angle $\frac{\pi}{4}$ with the vertical direction. The electric flux through the curved surface of the hemisphere is

$A$ point charge of $2.0 \; \mu C$ is at the centre of a cubic Gaussian surface $9.0 \; cm$ on edge. What is the net electric flux through the surface?