1. | \(8~\text{mC}\) | 2. | \(2~\text{mC}\) |
3. | \(5~\text{mC}\) | 4. | \(7~\mu \text{C}\) |
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. | \(\sqrt{2}qa\) along \(+y\) direction |
2. | \(\sqrt{2}qa\) 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. | \(\sqrt{2}qa\) along \(+x\) direction |
The net dipole moment of the system is of the magnitude:
1. \(q\times 2a\)
2. \(2q \times 2a\)
3. \(q\times a\)
4. \(2\times (2q\times 2a)\)
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. |
1. | \(\frac{1}{{R}^{6}}\) | 2. | \(\frac{1}{{R}^{2}}\) |
3. | \(\frac{1}{{R}^{3}}\) | 4. | \(\frac{1}{{R}^{4}}\) |
1. | \(10^{-2}~\text{N-m}\) |
2. | \(0\) |
3. | \(10^{-1}~\text{N-m}\) |
4. | \(0.01~\text{N-m}\) |
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 \(\overrightarrow{P}\) is given by:
(\(r\gg\) separation of two charges forming the dipole, \(\varepsilon_{0} =\) permittivity of free space)
1. | \(\overrightarrow{E}=\frac{\overrightarrow{P}}{4\pi \varepsilon _{0}r^{3}}\) | 2. | \(\overrightarrow{E}=\frac{2\overrightarrow{P}}{\pi \varepsilon _{0}r^{3}}\) |
3. | \(\overrightarrow{E}=-\frac{\overrightarrow{P}}{4\pi \varepsilon _{0}r^{2}}\) | 4. | \(\overrightarrow{E}=-\frac{\overrightarrow{P}}{4\pi \varepsilon _{0}r^{3}}\) |
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.