Electrostatics MCQs

In figure two positive charges q2 and q3 fixed along the y-axis, exert a net electric force in the +x-direction on a charge q1, fixed along the x-axis. If a positive charge Q is added at (x, 0), the force on q1 shall increase along the positive x-axis.

• shall increase along the positive x-axis

• shall decrease along the positive x-axis

• shall point along the negative x-axis

• shall increase but the direction changes because of the intersection of Q with q2 and q3

A point positive charge is brought near an isolated conducting sphere (figure). The electric field is best given by

The electric flux through the surface in Fig. (iv) is the largest.

• in Fig. (iv) is the largest

• in Fig. (iii) is the least

• in Fig. (ii) is same as Fig. (iii) but is smaller than Fig. (iv)

• is the same for all the figures

Five charges q1, q2, q3, q4 and q5 are fixed at their positions as shown in figure, S is a Gaussian surface. The Gauss’ law is given by Which of the following statements is correct?

• E on the LHS of the above equation will have a contribution from q1,q5 and q1, q5 and q3 while q on the RHS will have a contribution from q1 and q4 only

• E on the LHS of the above equation will have a contribution from all charges while q on the RHS will have a contribution from q2 and q4 only

• E on the LHS of the above equation will have a contribution from all charges while q on the RHS will have a contribution from q1,q3 and q5 only

• Both E on the LHS and q on the RHS will have contributions from q2 and q4 only

Figure shows electric field lines in which an electric dipole P is placed as shown. Which of the following statements is correct?

• The dipole will not experience any force

• The dipole will experience a force towards right

• The dipole will experience a force towards left

• The dipole will experience a force upwards

A point charge +q is placed at a distance d from an isolated conducting plane. The field at a point P on the other side of the plane is

• directed perpendicular to the plane and away from the plane

• directed perpendicular to the plane but towards the plane

• directed radially away from the point charge

• directed radially towards the point charge

A hemisphere is uniformly charged positively. The electric field at a point on a diameter away from the centre is directed.

• perpendicular to the diameter

• parallel to the diameter

• at an angle tilted towards the diameter

• at an angle tilted away from the diameter

If ФsE . dS = 0 over a surface, then

• the electric field inside the surface and on it is zero

• the electric field inside the surface is necessarily uniform

• the number of flux lines entering the surface must be equal to the number of flux lines leaving it

• all charges must necessarily be outside the surface

The electric field at a point is

• always continuous

• continuous if there is no charge at that point

• discontinuous only if there is a negative charge at that point

• discontinuous if there is a charge at that point

If there were only one type of charge in the universe, then