1) B) continuous direct.
2) B) oscillator.
3) C) Bismuth.
6) I dont know this one sorry :/
8) B) The electric potential (volts) divided by the current (amperes) equals the resistance (ohms).
11) D) 30 V
13) A) Each of the two segments of the original bar magnet will have a north and south pole.
16) C) Shortening the conductor.