The acceleration of an electron due to the mutual attraction between the electron and a proton when they are \(1.6~\mathring{A}\) apart is:
\(\left(\dfrac{1}{4 \pi \varepsilon_0}=9 \times 10^9~ \text{Nm}^2 \text{C}^{-2}\right)\)
1. | \( 10^{24} ~\text{m/s}^2\) | 2 | \( 10^{23} ~\text{m/s}^2\) |
3. | \( 10^{22}~\text{m/s}^2\) | 4. | \( 10^{25} ~\text{m/s}^2\) |
Polar molecules are the molecules:
1. | that acquires a dipole moment only when the magnetic field is absent. |
2. | has a permanent electric dipole moment. |
3. | has zero dipole moment. |
4. | that acquire a dipole moment only in the presence of an electric field due to displacement of charges. |
A dipole is placed in an electric field as shown. In which direction will it move?
1. | towards the left as its potential energy will decrease. |
2. | towards the right as its potential energy will increase. |
3. | towards the left as its potential energy will increase. |
4. | towards the right as its potential energy will decrease. |
A spherical conductor of radius \(10~\text{cm}\) has a charge of \(3.2 \times 10^{-7}~\text{C}\) distributed uniformly. What is the magnitude of the electric field at a point \(15~\text{cm}\) from the center of the sphere?
\(\dfrac{1}{4\pi \varepsilon _0} = 9\times 10^9~\text{N-m}^2/\text{C}^2\)
1. \(1.28\times 10^{5}~\text{N/C}\)
2. \(1.28\times 10^{6}~\text{N/C}\)
3. \(1.28\times 10^{7}~\text{N/C}\)
4. \(1.28\times 10^{4}~\text{N/C}\)
1. | \(\dfrac{1}{{R}^{6}}\) | 2. | \(\dfrac{1}{{R}^{2}}\) |
3. | \(\dfrac{1}{{R}^{3}}\) | 4. | \(\dfrac{1}{{R}^{4}}\) |
Twelve point charges each of charge \(q\) C are placed at the circumference of a circle of radius \(r\) m with equal angular spacing. If one of the charges is removed, the net electric field (in N/C) at the centre of the circle is:
(\(\varepsilon_0 \)-permittivity of free space)
1. | \(\dfrac{13q}{4\pi \varepsilon_0r^2}\) | 2. | zero |
3. | \(\dfrac{q}{4\pi \varepsilon_0r^2}\) | 4. | \(\dfrac{12q}{4\pi \varepsilon_0r^2}\) |
1. | the electric field inside the surface is necessarily uniform. |
2. | the number of flux lines entering the surface must be equal to the number of flux lines leaving it. |
3. | the magnitude of electric field on the surface is constant. |
4. | all the charges must necessarily be inside the surface. |