If you are coming to a stop at a stop sign and there is a tree close by what is used as the reference point? You, the tree, or the car Explain.

The Tree

Explanation:

The tree defines the location at which you are. The car might seem important if not for the fact that you are in it too and it's constantly moving so the reference point most definitely seems to be the tree.

the answer is the first electromagnet (a). this is because it has more coils around the ferromagnetic material. increasing the number of coils increases the surface area in which the metal interacts with the current in the coil. this enables more atoms in the metal to become aligned hence becoming more magnetized.