Two thin metal plates are placed close to each other. On the inner side, both plates have a surface charge density of 2.9 × 10−11 C m−2, but of opposite nature. Between the plates, what is the electric force exerted in per unit area ?
5.5 × 10 -11 N/m2
9.5 × 10 -11 N/m2
5.5 × 10 -12 N/m2
9.5 × 10 -12 N/m2
Four charges q, 2q, 3q and 4q are located at the vertices of a square of side a (as shown in the given figure). k is the electrostatic constant. What is the sum of the magnitude of forces exerted on each charge?
Two charged balls are suspended from a hinge by two threads of equal lengths. Mass of both the balls is 200 g. The amount of charges on both the balls is the same. At translational equilibrium, the balls are separated by a distance of 0.8 m, as shown in the given figure. What is the magnitude of charge on each ball?
4.33 µC
8.97 µC
17.16 µC
34.48 µC
The bob of a pendulum of mass 100 g is at equilibrium in a horizontal uniform electric field of 2.5 × 105 V m−1. In this equilibrium position, the pendulum makes an angle with the vertical. The amount of charge on the bob is 3 µC. Assume that the bob is suspended by means of a thin mass-less string. What will be the tension in the string when the bob is at equilibrium?
0.75 N
1.23 N
0.75 × 102 N
1.23 × 102 N
A rod carries a negative charge of magnitude 2.4 × 10−8 C. The length of the rod is 2.4 m and the radius of the cross-section is 9 mm. What is the electric field intensity at the mid point on the surface of the rod ?
4 × 104 N C -1
2 × 104 N C -1
−4 × 104 N C -1
−2 × 104 N C -1
An electric dipole of moment 7.2 × 10−8 C m is placed in a uniform electric field of magnitude 2.42 × 104 N C−1. Initially,the angle between the dipole and the field is zero. Then, the dipole is turned at 30° with respect to the direction of the electric field. What is the potential energy stored in the dipole in the given field ?
2.33 × 10−4 J
3.16 × 10−4 J
5.26 × 10−4 J
7.62 × 10−4 J
The electric field intensity vector in a region of space is given by The electric flux through a surface area of 50 m2 in x−y plane is:
100 N m2 C−1
150 N m2 C−1
200 N m2 C−1
450 N m2 C−1
There are three charges, , placed along a straight line of length 10 m, as shown in the given figure.
What is the net electrostatic force acting on charge q2?
12 × 10−3 N towards q1
28.5 × 10−3 N towards q1
12 × 10−3 N towards q3
28.5 × 10−3 N towards q3
A charge experiences a force of 32 N as it is placed at a certain distance on the axial line of an electric dipole.What will be the force on the charge if its distance from the dipole is halved?
64 N
128 N
256 N
512 N
