A toy car with charge \(q\) moves on a frictionless horizontal plane surface under the influence of a uniform electric field \(\vec E.\)Due to the force \(q\vec E,\) its velocity increases from \(0\) to \(6~\text{m/s}\) in a one-second duration. At that instant, the direction of the field is reversed. The car continues to move for two more seconds under the influence of this field. The average velocity and the average speed of the toy car between \(0\) to \(3\) seconds are respectively:
1. \(2~\text{m/s}, ~4~\text{m/s}\)
2. \(1~\text{m/s}, ~3~\text{m/s}\)
3. \(1~\text{m/s}, ~3.5~\text{m/s}\)
4. \(1.5~\text{m/s},~ 3~\text{m/s}\)
A thin conducting ring of radius \(R\) is given a charge \(+Q.\) The electric field at the centre O of the ring due to the charge on the part AKB of the ring is \(E.\) The electric field at the centre due to the charge on the part ACDB of the ring is:
1. \(3E\) along KO
2. \(E\) along OK
3. \(E\) along KO
4. \(3E\) along OK
Three-point charges + q, -2q and +q are placed at points (x=0, y=a, z=0), (x=0, y=0, z=0) and (x=a, y=0, z=0), respectively. The magnitude and direction of the electric dipole moment vector of this charge assembly are:
1. | qa along +y direction |
2. | qa along the line joining points (x=0, y= 0, z=0) and (x=a, y=a, z=0) |
3. | qa along the line joining points (x=0, y=0, z=0) and (x=a, y=a, z=0) |
4. | qa along +x direction |
A hollow cylinder has a charge q coulomb within it (at the geometrical centre). If ϕ is the electric flux in units of Volt-meter associated with the curved surface B, the flux linked with the plane surface A in units of volt-meter will be:
1.
2.
3.
4.
Find electric field due to a uniformly charged, long and thin rod
[This question includes concepts from 12th syllabus]
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. | zero as \(r\) increases for \(r<R\), decreases as \(r\) increases for \(r>R\). |
4. | zero as \(r\) increases for \(r<R\), increases as \(r\) increases for \(r>R\). |