Magnetic Field - General Physics - Solved Past Paper, Exams of Physics

Download Magnetic Field - General Physics - Solved Past Paper and more Exams Physics in PDF only on Docsity! 2. (20 pts) Given the arrangements shown below, clearly indicate the direction in which the current induced in the thick wire will flow. If you add some explanation as to why you chose the direction in each case, you might be more likely to get partial credit in the event of an incorrect answer. N S (a) (5 pts) Conducting ring falling towards a magnet. Magnetic field is up, and the flux is increasing. So the magnetic field from induced current must be down. In order for the field to be down, the current must flow as indicated above. + (b) (5 pts) Switch just closed. The current in the solenoid is going to be increas- ing in the direction shown by the small blue ar- rows. This will create an increasing magnetic field through the second loop, and pointing to the left. Thus the magnetic field from the induced current will be to the right. In order to produce this mag- netic field, the induced current must flow down in front, as indicated by the large blue arrow. (c) (5 pts) Loop moving down. The magnetic field is out and the flux is increasing. So the magnetic field from the induced current will be in. This requires a CW current flow. (d) (5 pts) Magnetic field decreasing in magnitude. The magnetic field is in and is decreasing. Thus the magnetic field from the induced current will also be in. To produce this field, the induced cur- rent needs to flow CW.