You have two cylindrical bar magnets with the same mass, length, and dipole moment, but different moments of inertia, I1 and I2. You place each bar magnet so that it is initially oriented perpendicular to a uniform magnetic field. When you let each bar magnet go from rest, you find that magnet 1 takes less time than magnet 2 to rotate so that it is parallel to the magnetic field. Is I1 greater than, less than, or equal to I2

;   is less than

Explanation:

Firstly, we take a look at the concept of moment of inertia, This concept comes from the fact that it resists change in motion. A body that has a higher value of moment of inertia requires more force ( torque) to change its position as compared to a body with lesser value of moment of inertia.

Now taking a look at the situation in  the question, both the magnets are placed in similar magnetic field, so having the same amount of force, hence torque acts on both magnets.

Since magnet 1 takes less time to rotate compared to magnate 2, hence magnet 1's moment of inertia should be less than that of magnet 2.

Therefore, ;   is less than

a.   mass number from atomic number

the minimum amperage that the current in this wire would have to have so that its weight is completely supported by the magnetic force due to earth's field, assuming that no other forces except gravity act on it