The force between two identical spheres charged with the same charge is $F$. If $75\%$ of the charge from one sphere is transferred to the other sphere,then the new force will be:

Two identical non-conducting solid spheres of same mass and charge are suspended in air from a common point by two non-conducting,massless strings of same length. At equilibrium,the angle between the strings is $\alpha$. The spheres are now immersed in a dielectric liquid of density $\rho_l = 800 \ kg \ m^{-3}$ and dielectric constant $K = 21$. If the angle between the strings remains the same after the immersion,then
$(A)$ electric force between the spheres remains unchanged
$(B)$ electric force between the spheres reduces
$(C)$ mass density of the spheres is $840 \ kg \ m^{-3}$
$(D)$ the tension in the strings holding the spheres remains unchanged

Two particles of equal mass $m$ and charge $q$ are placed at a distance of $16 \, cm$. They do not experience any net force. The value of $\frac{q}{m}$ is

Four charges are placed at the circumference of a dial clock as shown in the figure. If the clock has only an hour hand,then the resultant force on a charge $q_0$ placed at the center points in the direction which shows the time as (in $:30$)

Two similar spheres having $+q$ and $-q$ charge are kept at a certain distance $r$. $A$ force $F$ acts between them. If another similar sphere having $+q$ charge is kept in the middle of the two spheres, then it experiences a force in magnitude and direction as:

Two charges $q_1 = +6q$ and $q_2 = -3q$ are placed as shown in the figure. $A$ proton is placed on the $x$-axis away from $q_2$. To keep the proton in equilibrium,the distance between $q_1$ and the proton is: