The tiny ball at the end of the thread shown in figure has a mass of $0.5 \, g$ and is  placed in a horizontal electric field of intensity $500\, N/C$. It is in equilibrium in the  position shown. The magnitude and sign of the charge on the ball is .....$\mu C$

A drop of ${10^{ - 6}}\,kg$ water carries ${10^{ - 6}}\,C$ charge. What electric field should be applied to balance its weight (assume $g = 10\,m/{s^2}$)

Two parallel large thin metal sheets have equal surface charge densities $(\sigma = 26.4 \times 10^{-12}\,c/m^2)$ of opposite signs. The electric field between these sheets is

The electric field in a region is radially outward and at a point is given by $E=250 \,r V / m$ (where $r$ is the distance of the point from origin). Calculate the charge contained in a sphere of radius $20 \,cm$ centred at the origin ......... $C$

The distance between the two charges $25\,\mu C$ and $36\,\mu C$ is $11\,cm$ At what point on the line joining the two, the intensity will be zero

The linear charge density on upper half of a segment of ring is $\lambda$ and at lower half, it is $-\lambda$. The direction of electrical field at centre $O$ of ring is :-