The electric field at a point is:
a. | always continuous |
b. | continuous if there is no charge at that point |
c. | discontinuous only if there is a negative charge at that point |
d. | discontinuous if there is a charge at that point |
1. (a, b)
2. (b, d)
3. (c, d)
4. (a, d)
If \(\int_S E.ds = 0\) over a surface, then:
a. | the electric field inside the surface and on it is zero. |
b. | the electric field inside the surface is necessarily uniform. |
c. | the number of flux lines entering the surface must be equal to the number of flux lines leaving it. |
d. | all charges must necessarily be outside the surface. |
1. (a, c)
2. (b, c)
3. (c, d)
4. (a, d)
A hemisphere is uniformly charged positively. The electric field at a point on a diameter away from the centre is directed:
1. perpendicular to the diameter.
2. parallel to the diameter.
3. at an angle tilted towards the diameter.
4. at an angle tilted away from the diameter.
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:
1. | directed perpendicular to the plane and away from the plane. |
2. | directed perpendicular to the plane but towards the plane. |
3. | directed radially away from the point charge. |
4. | directed radially towards the point charge. |
The figure shows electric field lines in which an electric dipole p is placed as shown. Which of the following statements is correct?
1. | The dipole will not experience any force. |
2. | The dipole will experience a force towards the right. |
3. | The dipole will experience a force towards the left. |
4. | The dipole will experience a force upwards. |
Five charges q1, q2, q3, q4, and q5 are fixed at their positions as shown in the figure, S is a Gaussian surface. The Gauss' law is given by . Which of the following statements is correct?
1. | E on the LHS of the above equation will have contribution from q1, q5 and q3 while q on the RHS will have a contribution from q2 and q4 only. |
2. | 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. |
3. | 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. |
4. | Both E on the LHS and q on the RHS will have contributions from q2 and q4 only. |
The electric flux through the surface:
1. | in figure-(iv) is the largest |
2. | in figure-(iii) is the least |
3. | in figure-(ii) is same as figure-(iii) but is smaller than figure-(iv) |
4. | is the same for all the figures |
A point positive charge is brought near an isolated conducting sphere (figure). The electric field is best given by:
1. 2.
3. 4.
In the 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
1. shall increase along the positive x-axis.
2. shall decrease along the positive x-axis.
3. shall point along the negative x-axis.
4. shall increase but the direction changes because of the intersection of Q with q2 and q3.
A positive charge Q is uniformly distributed along a circular ring of radius R. A small test charge q is placed at the centre of the ring. Then,
a. | if q > 0 and is displaced away from the centre in the plane of the ring, it will be pushed back towards the centre. |
b. | if q < 0 and is displaced away from the centre in the plane of the ring, it will never return to the centre and will continue moving till it hits the ring. |
c. | if q < 0, it will perform SHM for small displacement along the axis. |
d. | q at the centre of the ring is in an unstable equilibrium within the plane of the ring for q > 0. |
1. (a, b, c)
2. (a, c, d)
3. (b, c, d)
4. (c, d)