A spherical shell of radius 10cm is carrying a charge q if the electric potential at distance 5cm i, 10cm and 15cm from the center of the spherical shell is v1 v2 and v3

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

Need to find the time taken for the dipole to come back to eqm