Question -
Answer -
(a) Zero at both the points
Charge − q is located at(0, 0, − a) and charge + q is located at (0,0, a). Hence, they form a dipole. Point (0, 0, z) is onthe axis of this dipole and point (x, y, 0) is normal to theaxis of the dipole. Hence, electrostatic potential at point (x, y,0) is zero. Electrostatic potential at point (0, 0, z) is given by,
Where,
= Permittivity of free space
p =Dipole moment of the system of two charges = 2qa
(b) Distance r is much greater thanhalf of the distance between the two charges. Hence, the potential (V)at a distance r is inversely proportional to square of thedistance i.e.
(c) Zero
The answer does not change if the path ofthe test is not along the x-axis.
A test charge is moved from point (5, 0, 0)to point (−7, 0, 0) along the x-axis. Electrostatic potential
Electrostatic potential, V2,at point (− 7, 0, 0) is given by,
Hence, no work is done in moving a smalltest charge from point (5, 0, 0) to point (−7, 0, 0) along the x-axis.
The answer does not change because workdone by the electrostatic field in moving a test charge between the two pointsis independent of the path connecting the two points.