Four dipoles having charge $\pm e$ are placed inside a sphere. The total flux of $\vec{E}$ coming out of the sphere is

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

What is called a Gaussian surface?

The electric field in a region is uniform and is given by $\vec{E} = a \hat{i} + b \hat{j} + c \hat{k}$. The electric flux associated with a surface of area $\vec{A} = \pi R^2 \hat{i}$ is:

$A$ point charge $q$ is placed at a distance $\frac{a}{2}$ directly above the centre of a square of side $a$. The electric flux through the square is

Select the correct statement$(s)$.
$(1)$ The tangent drawn at any point on an electric field line gives the direction of the force acting on a positive charge at that point.
$(2)$ The normal drawn at any point on an electric field line gives the direction of the force acting on a positive charge at that point.
$(3)$ Electric field lines start from a negative charge and end on a positive charge.
$(4)$ Electric field lines start from a positive charge and end on a negative charge.