magnetic induction

1. The connection described in Statement 2 cannot work. It is because the magnet will be continuously supplied with current and hence attract the hammer to the gong permanently.

2. When the magnet is pushed into the solenoid, induced current flows from the +ve to -ve terminals of the galvanometer. The pointer deflects to the right.
When the magnet is withdrawn, the induced current flows in the other way round, hence the pointer deflects to the left.
The answer is option D.

3. The first two methods will leave some "residue magnetism" on the steel rod.

4. The current in the coil makes Y to become a bar magnet, which repels X.

5. You apply right hand grip rule onto the coil. The direction pointed by the thumb will be the normal.

2014-10-22 15:34:58 補充：
2. If you look at the solenoid from the direction of the magnet, the induced current in the solenoid flows clockwise. Hence, the current flows from +ve to -ve terminals of the galvanometer.

2014-10-22 15:39:27 補充：
4. Both X and Y will be magnetized with the same polarity on the top and same polarity at the bottom, when the magnetic field produced by the coil is alternating upward and downward. Because like poles repel, Y will move away from X.

2014-10-22 15:47:30 補充：
5. Curl the other 4 fingers (not the thumb) of your right hand in the direction of current in the coil. Your thumb will then point in the direction of the -x axis, which gives you the direction of the normal.

2014-10-25 10:46:00 補充：
Your further question:
5. The angle between the normal and the plane of the coil enables you to calculate the torque acting on the coil.