A carpenter has a mix of both iron nails and plastic nails in a jar. For a job, he needs only the iron nails. What physical properties could help him separate the nails?

Magnetism

Explanation:

The carpenter can separate the iron nails from the plastic nails using a magnet. The iron nails have magnetic properties therefore they would be attracted to the magnet living only the plastic nails. This process is known as magnetic separation because it is based on the physical properties of the mixed components separating a mixture of components containing magnetic and non magnetic materials.

the answer to this is proletariats.

hope this : )

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.