On moving a charge of 20 coulomb by 2 cm, 2 J of work is done, then the potential difference between the points is
0.1 V
8 V
2 V
0.5 V
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 dielectric strength of air at NTP is 3 x 106 V/m. The maximum charge that can be given to a spherical conductor of radius 3 m is
3 x 104 C
3 x 10-3 C
3 x 10-2 C
3 x 10-1 C
A charge q is placed at the centre of the line joining two exactly equal positive charges Q. The system of three charges will be in equilibrium, if q is equal to
- Q/4
+ Q
- Q
Q/2
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
The negative electric flux indicates that the net flux through the surface is
inward
outward
outward or inward
none of the above
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
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
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
The study of the effects associated with electric charges at rest is called
electromagnetism
electrostatics
magnetostatics
none of these
