Difference between far point and near point

Far point = is the farthest point where you can see the object

near point= is the nearest distance where you can see the object.

Explanation:

The far point of human eye is upto infinity & the near point is 25cm.

area of focus

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.