Electric potential of earth is taken to be zero because earth is a good
dielectric
semiconductor
insulator
conductor
On moving a charge of 20 coluomb 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
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 field required to just support a water droplet of mass 10-5 g, which has a charge of 10-13 C is
107 V m-1
9.8 × 103 V m-1
106 V m-1
9.8 × 105 V m-1
Two spheres of radii r1 and r2 are charged to the same potential. If s1 and s2 are surface densities of charges on the two, then ratio is
The length of a given cylindrical wire is increased by 100%. Due to the consequent decrease in diameter the change in the resistance of the wire will be
200%
100%
50%
300%
There is an electric field E in x - direction. If the work done on moving a charge of 0.2 C through a distance of 2 m along a line making an angle 60o with x-axis is 4 J, then what is the value of E?
3 N/C
4 N/C
5 N/C
20 N/C
Two equally charged small balls A and B, placed at a fixed distance experience a force F. A similar uncharged ball C after touching one of them is placed at a middle point between the two balls. The force experienced by ball A, is
2F
4F
The four capacitors, each of 25 μF are connected as shown in figure. The DC voltmeter reads 200 V. The charge on one each plate of capacitor is