Consider the situation when almost all of the magnetic moments of a sample of a particular ferromagnetic metal are aligned. in this case, the magnetic field can be calculated as the permeability constant μ0 multiplied by the magnetic moment per unit volume. in a sample of iron, for example, where the number density of atoms is approximately 8.50 ✕ 1028 atoms/m3, the magnetic field can reach 1.99 t. if each electron contributes a magnetic moment of 9.27 ✕ 10−24 a · m2 (1 bohr magneton), how many electrons per atom contribute to the saturated field of iron?

2.00976

Explanation:

B = Magnetic field = 1.99 T

= Vacuum permeability =

= Magnetic moment of each electron =

n = Number density of atoms =

N = Number of electrons per atom

Magnetic field is given by

The number of electrons per atom contribute to the saturated field of iron is 2.00976

work: w = fd (given)

work done by chet   =50*1 = 50 j

work done by mika =40*2 = 80 j

work done by sara =30*1.5 = 45 j

work done by bill =60*0.5 = 30 j

students in order from the greatest amount of work done to the least is mika> chet> sara> bill

hence option (b) is correct.

it is very well related to a lot of things but with my limited knowledge i can confidently say that the answer is space.