The acceleration of an electron due to the mutual attraction between the electron and a proton when they are \(1.6~\mathring{\mathrm{A}}\) apart is:
( \(\frac{1}{4 \pi \varepsilon_0}=9 \times 10^9~ \mathrm{Nm}^2 \mathrm{C}^{-2}\) )
1. | \( 10^{24} \mathrm{~m} / \mathrm{s}^2 \) | 2 | \( 10^{23} \mathrm{~m} / \mathrm{s}^2 \) |
3. | \( 10^{22} \mathrm{~m} / \mathrm{s}^2 \) | 4. | \( 10^{25} \mathrm{~m} / \mathrm{s}^2\) |
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. |
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. | \(\vec{E}=-\frac{\vec{P}}{4\pi \epsilon _{0}r^{3}}\) |
A charge \(q\) is placed in a uniform electric field \(E.\) If it is released, then the kinetic energy of the charge after travelling distance \(y\) will be:
1. \(qEy\)
2. \(2qEy\)
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. | \(E\) |
In Millikan oil drop experiment, a charged drop falls with a terminal velocity v. If an electric field E is applied vertically upwards it moves with terminal velocity 2v in upward direction. If electric field reduces to E/2 then its terminal velocity will be:
1. v/2
2. v
3. 3v/2
4. 2v
Refer to the arrangement of charges in the figure and a Gaussian surface of radius R with Q at the centre. Then:
a. | total flux through the surface of the sphere is . |
b. | field on the surface of the sphere is . |
c. | flux through the surface of the sphere due to 5Q is zero. |
d. | field on the surface of the sphere due to -2Q is the same everywhere. |
Choose the correct statement(s):
1. a and d
2. a and c
3. b and d
4. c and d
If there were only one type of charge in the universe, then,
1. | on any surface. |
2. | if the charge is outside the surface. |
3. | could not be defined. |
4. | if charges of magnitude q were inside the surface. |
Two point dipoles of dipole moment and are at a distance x from each other and . The force between the dipole is:
1.
2.
3.
4.
A hollow metal sphere of radius \(R\) is uniformly charged. The electric field due to the sphere at a distance \(r\) from the centre:
1. | decreases as \(r\) increases for \(r<R\) and for \(r>R\). |
2. | increases as \(r\) increases for \(r<R\) and for \(r>R\). |
3. | is zero as \(r\) increases for \(r<R\), decreases as \(r\) increases for \(r>R\). |
4. | is zero as \(r\) increases for \(r<R\), increases as \(r\) increases for \(r>R\). |