Two fixed charges $4\,Q$ (positive) and $Q$ (negative) are located at $A$ and $B$, the distance $AB$ being $3$ $m$.
The point $P$ where the resultant field due to both is zero is on $AB$ outside $AB$.
If a negative charge is placed at $P$ and displaced slightly along $AB $ it will execute oscillations.
If a positive charge is placed at $P$ and displaced slightly along $AB$ it will execute oscillations.
$A$ and $B$ both
Two identical balls having like charges and placed at a certain distance apart repel each other with a certain force. They are brought in contact and then moved apart to a distance equal to half their initial separation. The force of repulsion between them increases $4.5$ times in comparison with the initial value. The ratio of the initial charges of the balls is
Two identical conducing spheres having unequal positive charges $q_1$ and $q_2$ separated by distance $r$. If they are made to touch each other and then separated again to the same distance. The electrostatic force between the spheres in this case will be (neglect induction of charges)
$A$ and $B$ are two identical blocks made of a conducting material. These are placed on a horizontal frictionless table and connected by a light conducting spring of force constant $‘K’$. Unstretched length of the spring is $L_0$. Charge $Q/2$ is given to each block. Consequently, the spring stretches to an equilibrium length $L$. Value of $Q$ is
The ratio of gravitational force and electrostatic repulsive force between two electrons is approximately (gravitational constant $=6.7 \times 10^{-11} \,Nm ^2 / kg ^2$, mass of an electron $=9.1 \times 10^{-31} \,kg$, charge on an electron $=1.6 \times 10^{-19} C$ )
A charge of $Q$ coulomb is placed on a solid piece of metal of irregular shape. The charge will distribute itself