stroking the coil with a piece of silk heating the coil uniformly laying the coil near a magnet rotating the coil in a magnetic field
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Which is the best way to generate an electrical current in a coil of wire?
Possibilities:
- stroking the coil with a piece of silk
- heating the coil uniformly
- laying the coil near a magnet
- rotating the coil in a magnetic field

rotating the coil in a magnetic field