To solve this exercise it is necessary to use the concepts related to Difference in Phase.
The Difference in phase is given by

Where
Horizontal distance between two points
Wavelength
From our values we have,


The horizontal distance between this two points would be given for

Therefore using the equation we have




Therefore the correct answer is C.
Perpendicular acceleration:
F = ma
a = 4 / 2 = 2 m/s²
Perpendicular distance:
s = ut + 1/2 at²
s = 0 x 4 + 1/2 x 2 x 4²
s = 16 m
Horizontal distance:
s = ut
= 3 x 4
= 12 m
Total distance = √(12² + 16²)
= 20 m.
In step 1, to increase the potential energy, the iron will move towards the electromagnet.
In step 2, to increase the potential energy, the iron will move towards the electromagnet.
<h3>Potential energy of a system of magnetic dipole</h3>
The potential energy of a system of dipole depends on the orientation of the dipole in the magnetic field.

where;
is the dipole moment- B is the magnetic field


Increase in the distance (r) reduces the potential energy. Thus, we can conclude the following;
- In step 1, to increase the potential energy, the iron will move towards the electromagnet.
- In step 2, when the iron is rotated 180, it will still maintain the original position, to increase the potential energy, the iron will move towards the electromagnet.
Learn more about potential energy in magnetic field here: brainly.com/question/14383738
There are many processes to get nuclear energy. Nuclear energy is basically energy from an atom. For example fission is where the nucleus of an atom ( typically radioactive atoms ) gets split then energy is released ( typically heat). And in radioactive decay radiation is released from an radioactive atom. Hope this helps