Three charges $ - {q_1},\,\, + {q_2}$ and $ - {q_3}$ are placed as shown in the figure. The $x$-component of the force on $ - {q_1}$ is proportional to
$\frac{{{q_2}}}{{{b^2}}} - \frac{{{q_3}}}{{{a^2}}}\,\sin \theta $
$\frac{{{q_2}}}{{{b^2}}} - \frac{{{q_3}}}{{{a^2}}}\,\cos \theta $
$\frac{{{q_2}}}{{{b^2}}} + \frac{{{q_3}}}{{{a^2}}}\,\sin \theta $
$\frac{{{q_2}}}{{{b^2}}} + \frac{{{q_3}}}{{{a^2}}}\,\cos \theta $
Two small spherical balls each carrying a charge $Q = 10\,\mu C$ ($10\, micro-coulomb$) are suspended by two insulating threads of equal lengths $3\, m$ each, from a point fixed in the ceiling. It is found that in equilibrium threads are separated by an angle $120^o$ between them, as shown in the figure. What is the tension in the threads (Given : $\frac{1}{{\left( {4\pi {\varepsilon _0}} \right)}} = 9 \times {10^9}\,Nm/{C^2}$)
A proton is fired at an initial velocity of $150 \,m/s$ at an angle of $60^o $ above the horizontal into a uniform electric field of $2 \times 10^{-4} \,N/C$ between two charged parallel plates as shown in figure. Then the total time the particle is in motion is :-
The electric field between the two spheres of a charged spherical condenser
Four charges equal to $-Q$ are placed at the four corners of a square and a charge $q$ is at its centre. If the system is in equilibrium the value of $q$ is
Three point charges of magnitude $5 \mu C , 0.16 \mu C$ and $0.3 \mu C$ are located at the vertices $A , B , C$ of a right angled triangle whose sides are $AB =3\,cm$, $BC =3 \sqrt{2}\,cm$ and $CA =3\,cm$ and point $A$ is the right angle corner. Charge at point $A$ experiences
$N$ of electrostatic force due to the other two charges.