Q. No.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. \(1.28\times 10^{4}~\text{N/C}\)
\(\left(\frac{1}{4\pi \varepsilon _0} = 9\times 10^9~\text{N-m}^2/\text{C}^2\right)\)
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. \(1.28\times 10^{4}~\text{N/C}\)
1. \(6 \times 10^{-3}~\text{N}\)
2. \(5 \times 10^{-3}~\text{N}\)
3. \(4 \times 10^{-4}~\text{N}\)
4. \(5 \times 10^{-4}~\text{N}\)
The electrostatic force on a small sphere of charge 0.4 µC due to another small sphere of charge –0.8 µC in the air is 0.2 N. The distance between the two spheres is:
1. 14 cm
2. 12 cm
3. 16 cm
4. 10 cm
1. \(2\) N
2. \(1\) N
3. \(5\) N
4. \(0\) N
1. \(4.5\times10^{6}~\text{N/C along}~OA\)
2. \(5.4\times10^{6}~\text{N/C along}~OA\)
3. \(4.5\times10^{6}~\text{N/C along}~OB\)
4. \(5.4\times10^{6}~\text{N/C along}~OB\)
A spherical conductor of radius \(12~\text{cm}\) has a charge of \(1.6\times10^{-7}~\text{C}\) distributed uniformly on its surface. The electric field just outside the sphere is:
| 1. | \(\text{zero}\) | 2. | \(10^5~ \text{NC}^{-1} \) |
| 3. | \(10^{-5}~ \text{NC}^{-1} \) | 4. | \(10^{6 }~ \text{NC}^{-1} \) |
A system has two charges, \(q_\mathrm{A} = 2.5 \times 10^{-7}~\text{C}\) and \(q_\mathrm{B} = -2.5 \times 10^{-7}~\text{C}\), is located at points \(\mathrm{A}\): \((0,0,-15~\text{cm})\) and \(\mathrm{B}\): \((0,0,+15~\text{cm})\) respectively. The electric dipole moment of the system is:
| 1. | \(7.5\times 10^{-8}~\text{C-m}\) (along negative z-axis) |
| 2. | \(8.5\times 10^{-8}~\text{C-m}\) (along positive z-axis) |
| 3. | \(5.5\times 10^{-8}~\text{C-m}\) (along positive z-axis) |
| 4. | \(3.5\times 10^{-8}~\text{C-m}\) (along negative z-axis) |
| 1. | \(2\times 10^{-5}~\text{N-m}\) | 2. | \(10^{-4}~\text{N-m}\) |
| 3. | \(10^{-5}~\text{N-m}\) | 4. | \(2\times 10^{-4}~\text{N-m}\) |
Which of the following statements about electric field lines (due to static charges) is incorrect?
| 1. | electric field lines never cross each other at any point. |
| 2. | electric field lines do not form any closed loop. |
| 3. | electric field lines can not be taken as continuous curves. |
| 4. | electric field lines start from a positive charge and end on a negative charge. |
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