Charges are placed on the vertices of a square as shown in the figure. Let $\vec{E}$ be the electric field and $V$ be the electric potential at the center. If the charges at $A$ and $B$ are interchanged with those at $D$ and $C$ respectively,then:

The dimension of $\frac{1}{2} \varepsilon_0 E^2$,where $\varepsilon_0$ is the permittivity of free space and $E$ is the electric field,is:

Five balls marked $a$ to $e$ are suspended using separate threads. Pairs $(b, c)$ and $(d, e)$ show electrostatic repulsion,while pairs $(a, b)$,$(c, e)$,and $(a, e)$ show electrostatic attraction. The ball marked $a$ must be:

An inclined plane making an angle $30^{\circ}$ with the horizontal is placed in a uniform horizontal electric field of $100 \ Vm^{-1}$ as shown in the figure. $A$ small block of mass $1 \ kg$ and charge $0.01 \ C$ is allowed to slide down from rest from a height $h=1 \ m$. If the coefficient of friction is $0.2$,then the acceleration of the block is nearly,
(Acceleration due to gravity,$g=10 \ ms^{-2}$) (in $ms^{-2}$)

Given below are two statements:
Statement-$I$: $A$ point charge is brought into an electric field. The value of the electric field at a point near the charge may increase if the charge is positive.
Statement-$II$: An electric dipole is placed in a non-uniform electric field. The net electric force on the dipole will not be zero.
Choose the correct answer from the options given below:

$A$ particle of mass $m$ and charge $q$ is thrown in a region where uniform gravitational field and electric field are present. The path of the particle: