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. |
A polythene piece rubbed with wool is found to have a negative charge of \(3 \times10^{-7}~\text{C}\). Transfer of mass from wool to polythene is:
1. \(0.7\times10^{-18}~\text{kg}\)
2. \(1.7\times10^{-17}~\text{kg}\)
3. \(0.7\times10^{-17}~\text{kg}\)
4. \(1.7\times10^{-18}~\text{kg}\)
Two insulated charged copper spheres A and B have their centers separated by a distance of 50 cm. What is the mutual force of electrostatic repulsion if the charge on each is ? The radii of A and B are negligible compared to the distance of separation.
1. 1.52 × 10−2 N
2. 3.7 × 10−2 N
3. 2.01 × 10−2 N
4. 2.23 × 10−1 N
The figure below shows tracks of three charged particles in a uniform electrostatic field. Which particle has the highest charge to the mass ratio?
1. 2
2. 3
3. 1
4. 1 and 3
What is the flux of electric field through a square of 10 cm on a side whose plane is parallel to the y z – plane?
1. \(15\ N\ m^{2}/C\)
2.\(10\ N\ m^{2}/C\)
3.\(30 \ N\ m^{2}/C\)
4.0
The electric field at the surface of a black box indicates that the net outward flux through the surface of the box is \(8.0\times10^{3}\) N-m2/C. What is the net charge inside the box?
1. \(1.01\) \(\mu\)C
2. \(0.01\) \(\mu\)C
3. \(0.03\) \(\mu\)C
4. \(0.07\) \(\mu\)C
A point charge + 10 μC is at a distance 5 cm directly above the centre of a square of side 10 cm, as shown in the figure. What is the magnitude of the electric flux through the square?
1.
2.
3.
4.
A point charge of 2.0 μC is at the center of a cubic Gaussian surface 9.0 cm on edge. What is the net electric flux through the surface?
1. 2.26 × 105 N m2 C-1
2. 2.09 × 105 N m2 C-1
3. 4.33 × 105 N m2 C-1
4. 4.71 × 105 N m2 C-1
A point charge causes an electric flux of to pass through a spherical Gaussian surface of 10.0 cm radius centered on the charge. If the radius of the Gaussian surface were doubled, how much flux would pass through the surface?
1. - 2.0×103 N m2/ C
2. - 1.0 ×103 N m2/ C
3. 2.0 ×103 N m2/ C
4. 0
A conducting sphere of radius \(10\) cm has an unknown charge. If the electric field, \(20\) cm from the centre of the sphere is \(1.5\times10^3\) N/C and points radially inward, what is the net charge on the sphere?
1. \(-5.70\) nC
2. \(-6.67\) nC
3. \(6.67\) nC
4. \(5.70\) nC