The potential of a point A is -500 V and that of another point B is +500 V. The work done by an external agent to take 2 units of negative charge from B to A is
+1000 J
-1000 J
+2000 J
-2000 J
Two spherical conductors A and B of radii 1 mm and 2 mm are separated by a distance of 5 cm and are uniformly charged. If the spheres are connected by a conducting wire then in equilibrium condition, the ratio of the magnitude of the electric fields at the surfaces of spheres A and B is
4 : 1
1 : 2
2 : 1
1 : 4
Some charge is being given to a conductor, then its potential is
maximum at surface
maximum at centre
same throughout the conductor
maximum somewhere between surface and centre
The formation of a dipole is due to two equal and dissimilar point charges placed at a
short distance
long distance
above each other
none of the above
The electric potential V at any point (x1, y1, z1) in space is given by V = 4x2 volt. The electric field at (1, 0, 2) m in Vm-1 is
8, along negative x-axis
8, along positive x-axis
16, along negative x-axis
16, along positive y-axis
A point Q lies on the perpendicular bisector of an electric dipole of dipole moment p. If the distance of Q from the dipole is r, (much larger than the size of the dipole) then electric field at Q is proportional to
p-1 and r2
p and r-2
p2 and r-3
p and r-3
An electric dipole, consisting of two opposite charges of 2 x 10-6 C each separated by a distance 3 cm is placed in an electric field of 2 x 105N/C. Torque on the dipole is
12 x 10-1 Nm
12 x 10-2 Nm
12 x 10-3 Nm
12 x 10-4 Nm
The negative electric flux indicates that the net flux through the surface is
inward
outward
outward or inward
When air is replaced by a dielectric medium of constant K, the maximum force of attraction between two charges, separated by a distance.
decreases K times
increases K times
remains unchanged
becomes 1/K2 times
Two concentric spheres of radii R and r have similar charges with equal surface densities (σ). What is the electric potential at their common centre?
none of these
