Consider a current carrying wire (current \(\text{I}\)) in the shape of a circle. Note that as the current progresses along the wire, the direction of \(\text{j}\) (current density) changes in an exact manner, while the current \(\text{I}\) remains unaffected. The agent that is essentially responsible for it is:
1. | source of emf. |
2. | the electric field produced by charges accumulated on the surface of the wire. |
3. | the charges just behind a given segment of wire which push them just the right way by repulsion. |
4. | the charges ahead. |
Which of the following characteristics of electrons determines the current in a conductor?
1. | Drift velocity alone. |
2. | Thermal velocity alone. |
3. | Both drift velocity and thermal velocity. |
4. | Neither drift nor thermal velocity. |