Consider an arbitrary electrostatic field configuration. A small test charge is placed at a null point (i.e., where E = 0) of the configuration. Show that the, equilibrium of the test charge is necessarily unstable

A small test charge is released at rest at a point in an electrostatic field configuration . Will it travel along the field line passing through that point ?

A short bar magnet placed on a horizontal plane has its axis aligned along the magnetic north- south direction . Null points are found on the magnet . The earth's magnetic field at the place is 0.36G . What is the magnet at the total magnetic field on the normal bisector of the same distance as the null points (i.e., 14 cm) from the centre of the magnet (at null points , field due to a magnet is equal and opposite to the horizontal component of earth's magnetic field . )

Two negative charges each of 1 unit and a positive charge q are placed on a straight line. Where should the charge q be placed and what should be its value for equilibrium of the charges? Is this equilibrium stable, unstable or neutral ?

A charge q=1muc is placed at a point (1m, 2m, 4m). The electric field at a point P(0,-4m, 3m) .

Due to an electric charge Q , field intensity at the position of test charge q_0 is vecE . If the test charge is replaced by -q_0 , then field intensity becomes

ABC is an equilateral triangle. Charge +q is placed at each corner. The electric field intensity at point 0 will be

Why the test charge is taken to be very small in the definition of electric field intensity?