An electric dipole is placed at an angle of \(30^\circ\) with an electric field intensity \(2\times10^5~ \mathrm{N/C}\). It experiences a torque equal to \(4 ~\mathrm{Nm}\). The charge on the dipole, if the dipole length is \(2~ \mathrm{cm}\), is:
1. | \(8~\mathrm{mC}\) | 2. | \(2~\mathrm{mC}\) |
3. | \(5~\mathrm{mC}\) | 4. | \(7~\mu \mathrm{C}\) |
Three-point charges + q, -2q and +q are placed at points (x=0, y=a, z=0), (x=0, y=0, z=0) and (x=a, y=0, z=0), respectively. The magnitude and direction of the electric dipole moment vector of this charge assembly are:
1. | qa along +y direction |
2. | qa along the line joining points (x=0, y= 0, z=0) and (x=a, y=a, z=0) |
3. | qa along the line joining points (x=0, y=0, z=0) and (x=a, y=a, z=0) |
4. | qa along +x direction |
An electric dipole is placed at the centre of a sphere. Which of the following statements is correct?
1. | The electric flux through the sphere is zero. |
2. | The electric field is zero at every point on the sphere. |
3. | The electric field is zero at every point inside the sphere. |
4. | The electric field is uniform inside the sphere. |
The net dipole moment of the system is of the magnitude:
1. q 2a
2. 2q 2a
3. q a
4. 2 (2q 2a)
In a certain region of space, the electric field is along the z-direction throughout. The magnitude of the electric field is, however, not constant but increases uniformly along the positive z-direction, at the rate of 105 NC-1 per meter. What is the torque experienced by a system having a total dipole moment equal to in the negative z-direction?
1. | 2. | ||
3. | 4. |
The electric field at the equator of a dipole is \(E.\) If the strength of the dipole and distance are now doubled, then the electric field will be:
1. | \(E/2\) | 2. | \(E/8\) |
3. | \(E/4\) | 4. | \(E\) |
An electric dipole is kept in a uniform electric field such that the dipole moment is not collinear with the electric field. It experiences:
1. | a force and torque. |
2. | a force but no torque. |
3. | a torque but no force. |
4. | neither a force nor a torque. |
The electric field at a point on the equatorial plane at a distance \(r\) from the centre of a dipole having dipole moment is given by:
(r >> separation of two charges forming the dipole, \(\epsilon_{0} =\) permittivity of free space)
1. | \(\vec{E}=\frac{\vec{P}}{4\pi \epsilon _{0}r^{3}}\) | 2. | \(\vec{E}=\frac{2\vec{P}}{\pi \epsilon _{0}r^{3}}\) |
3. | \(\vec{E}=-\frac{\vec{P}}{4\pi \epsilon _{0}r^{2}}\) | 4. | \(\vec{E}=-\frac{\vec{P}}{4\pi \epsilon _{0}r^{3}}\) |
An electric dipole is kept at the origin as shown in the diagram. The point A, B, C are on a circular arc with the centre of curvature at the origin. If the electric fields at A, B and C respectively are , then which of the following is incorrect? \(\left ( d\gg l \right )\)
1.
2.
3.
4.
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. |