Using keplers 3rd law, if a planet is 47 aus away from the sun, what ks its orbital period

option number c is the right answer.

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.