Part a: distance conversions
1. earth's diameter is 12.756 kilometers. how many meters is this?

12756000 m

Explanation:

In fact the actual diameter of the Earth is approximately not . So, let’s work with the first one.

A kilometer is equivalent to 1000 meters:

Knowing this, we can make the conversion:

This is Earth's diameter in meters

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.