Q. No.| 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. |
| 1. | \(2~\text{mC}\) | 2. | \(8~\text{mC}\) |
| 3. | \(6~\text{mC}\) | 4. | \(4~\text{mC}\) |
According to Gauss's law in electrostatics, the electric flux through a closed surface depends on:
| 1. | the area of the surface |
| 2. | the quantity of charges enclosed by the surface |
| 3. | the shape of the surface |
| 4. | the volume enclosed by the surface |
| 1. | \(\dfrac{Q}{\varepsilon_0}\times10^{-6}\) | 2. | \(\dfrac{2Q}{3\varepsilon_0}\times10^{-3}\) |
| 3. | \(\dfrac{Q}{6\varepsilon_0}\times10^{-3}\) | 4. | \(\dfrac{Q}{6\varepsilon_0}\times10^{-6} \) |
The magnitude of electric field intensity at a distance \({R}~(R \gg L )\) varies as:
| 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 \(q~\text C\) are placed at the circumference of a circle of radius \(r~\text{m}\) with equal angular spacing. If one of the charges is removed, the net electric field (in \(\text{N/C}\)) at the centre of the circle is:
(\(\varepsilon_0\text- \)permittivity of free space)
| 1. | \(\dfrac{13q}{4\pi \varepsilon_0r^2}\) | 2. | zero |
| 3. | \(\dfrac{q}{4\pi \varepsilon_0r^2}\) | 4. | \(\dfrac{12q}{4\pi \varepsilon_0r^2}\) |
(Given that the charge of the proton and electron each \(=1.6\times 10^{-19},\) the mass of the electron \(=9.11\times 10^{-31}~\text{kg},\) the mass of the proton \(=1.67\times 10^{-27}~\text{kg}\) )
1. \(10^{20}\)
2. \(10^{30}\)
3. \(10^{40}\)
4. \(10\)
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 centre of the sphere?
\(\left(\frac{1}{4\pi \varepsilon _0} = 9\times 10^9~\text{N-m}^2/\text{C}^2\right)\)
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. \(1.28\times 10^{4}~\text{N/C}\)
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