An electric dipole is in unstable equilibrium in the uniform electric field. The angle between its dipole moment and the electric field is
1. 90
2. 120
3. 0
4. 180
An electric dipole of dipole moment p is placed in an electric field of intensity E such that angle between electric field and dipole moment is . Assuming that the potential energy of the dipole is zero when , the potential energy of the dipole will be
(1) -pE cos
(2) pE(1-cos)
(3) pE(cos-1)
(4) -2pE(cos-1)
Eight dipoles of charges of magnitude \((e)\) are placed inside a cube. The total electric flux coming out of the cube will be:
1. \(\frac{8e}{\epsilon _{0}}\)
2. \(\frac{16e}{\epsilon _{0}}\)
3. \(\frac{e}{\epsilon _{0}}\)
4. zero
An electric dipole is situated in an electric field of uniform intensity E whose dipole moment is p and moment of inertia is I. If the dipole is displaced slightly from the equilibrium position, then the angular frequency of its oscillations is?
1.
2.
3.
4.
Two-point charges +q and –q are held fixed at (–d, 0) and (d, 0) respectively of a (x, y) coordinate system. Then
(1) E at all points on the y-axis is along
(2) The electric field at all points on the x-axis has the same direction
(3) Dipole moment is 2qd directed along
(4) Work has to be done in bringing a test charge from infinity to the origin
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 |
Two short dipoles are placed at a certain distance exert a force 'F' on each other. If the distance between them is doubled then the force will become
1. F
2.
3. 4F
4.
The net dipole moment of the system is of the magnitude:
1. q 2a
2. 2q 2a
3. q a
4. 2 (2q 2a)
A point charge +q is kept at the center of the curvature of thin semicircular wire of length l as shown. The wire has uniformly distributed charge -q on it. The dipole moment of the system is
1.
2.
3.
4. Zero
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. |