What is the power dissipated by a 50.0 ohm resistor?

a. 0.743 w
b. 1.49 w
c. 2.08 w
d. 12.5w
e. none of these

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.

365.25 earth days are in the year of a light year

one "light year" is the distance that light travels, through vacuum, in one julian year.   that's 365.25 days, of 24 hours each.