III. Faraday\'s law Two loops of the same radius are held near a solenoid. Both
ID: 1864654 • Letter: I
Question
III. Faraday's law Two loops of the same radius are held near a solenoid. Both loops are at the same distance from the end of the solenoid and from the axis of the A. The two loops are made of two different conducting materials. The Lop 1 resistance of loop 2 is greater than that of loop 1. 1. Is there a current induced in either of the loops: Loop 2 .Before the switch is closed? Explain. Just after the switch is closed? Explain. .A long time after the switch is closed? Explain. 2. When there is a current, in which direction does it flow? 3. The ratio of the induced currents in the two loops is experimentally found to be equal to the inverse of the ratio of the resistances of the loops. What does this imply about the ratio of the induced emf in the loops? B. Loop 2 is now replaced by a wooden loop . Is there still an emf in the loop?Explain. If there still a current induced in the loop? Explain. C. Loop 2 is now completely removed. Consider the circular path that the wire of loop 2 used to occupy. Is there still an emf along the path? Explain. Is there a current along the path? Explain.Explanation / Answer
A.
. Before the switch is closed, there is no magnetic field or flux present in the space and since the loops are electrically isolated from the battery, hence there is no current/emf induced in the loops
. Just after the switch is closed there is a rate of change of current in the solenoid hence there is a rate of change of magnetic field produced by it hence it produces a time varying magnetic flux linked with the loops hence it induces current in the loops.
. After long time, the magnetic field hence the flux is constant due to steady state condition hence there is no current induced in the loops.
2. The current in the loops flows in the Clockwise direction as it has to oppose the rate of change of flux through it which is due to solenoid forming a South pole in front of loops due to battery polarity.
3. The emf induced in both the loops is same then only the current will have sole dependency on resistances of the loops, hence we can infer that there is equal emf induced in both the loops.
B.Time varying magnetic flux produces electric field, the corresponding electric field has a direction in such a manner that there are concentric circles of electric field in the area associated with magnetic flux, these concentric field lines create potential difference along the circular path which appears as a induced emf. Since we do not have any free electrons in wood hence we won't onserve any current flow but there would be an emf induced.
C. As explained in Part B there would be a potential difference along the path, hence induced emf but as there is no charge carrier present there can't be any current along the path