Suppose that, when sampled at a rate of N = 8, a particular signal is given as: f = 3e0 − 2e1 + e4 − 7e7. What would the signal look like, in terms of the standard basis, if sampled at a frequency of N = 4?

good for her? ? where is the question?

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.