Answer:
4. C, B, D, A
Step-by-step explanation:
This is a simple experiment to make electromagnets. Electromagnets are the instrument/object which behave like magnet when electricity is passed around them. As long as electricity is supplied they will behave like magnet. When the electricity is stopped, they will no longer behave like magnet.
The correct sequence, as per the question, to make electromagnet are listed below:
Wrap a wire to create loops around a piece of metal, such as iron. (As of now it will not behave like magnet)
As soon as we close the circuit, current starts flowing through the loops and generate magnetic field.
This magnetic field forces the magnetic domains inside metal piece to align and the metal starts behaving like a magnet.