Explanation:
First, we will calculate the electric potential energy of two charges at a distance R as follows.
R = 2r
= 
= 0.2 m
where, R = separation between center's of both Q's. Hence, the potential energy will be calculated as follows.
U = 
= 
= 0.081 J
As, both the charges are coming towards each other with the same energy so there will occur equal sharing of electric potential energy between these two charges.
Therefore, when these charges touch each other then they used to posses maximum kinetic energy, that is,
.
Hence, K.E = 
= 
= 0.0405 J
Now, we will calculate the speed of balls as follows.
V = 
= 
= 0.142 m/s
Therefore, we can conclude that final speed of one of the balls is 0.142 m/s.
If a volcano epulses massive amounts of dust into the atmosphere, those two things will/can happen.
The events will last until the dust lays down on the earth.
Let us start from considering monochromatic light as an incidence on the film of a thickness t whose material has an index of refraction n determined by their respective properties.
From this point of view part of the light will be reflated and the other will be transmitted to the thin film. That additional distance traveled by the ray that was reflected from the bottom will be twice the thickness of the thin film at the point where the light strikes. Therefore, this relation of phase differences and additional distance can be expressed mathematically as

We are given the second smallest nonzero thickness at which destructive interference occurs.
This corresponds to, m = 2, therefore


The index of refraction of soap is given, then

Combining the results of all steps we get

Rearranging, we find



Answer:
The magnetic field is strongest at the center and weakest between the two poles just outside the bar magnet. The magnetic field lines are densest at the center and least dense between the two poles just outside the bar magnet.
Explanation: