2 conducting spherical shell have radii a=3cm nd b=6cm is filled with a dielectric of Er=8.A portion of dielectric is now removed so that E_r=1 for 0＜phi_r=8 for pi/2

Electrostatics question based on earthing of spherical shell

an object has a charge of 2c and gains 10^19 electrons. the net chaarge on the object becomes??

A wire with a linear charge density lambda forms a quarter of a cjrclenof radius R and is placed asa shown in thefigure with its centre of curvature at the origin O the electric field at O will be

Find the value of q so that system remains in equilibrium.. figure attached below

Find the value of q so that system remains in equilibrium