B) 7.87 m/s
The gravitational pull is the rate of change of velocity which is the acceleration. Formula for acceleration is;

Given:
• Initial velocity = 0m/s; I dropped the ball, and didn't throw it, so it was at rest firstly
• Time taken = 2.40s
• Acceleration = 3.28m/s^2
We're require to find the final velocity, at which the ball hit the ground with. Ignoring air resistance, keep in mind that the velocity of an object increases as it comes closer to the ground.


Answer:

Explanation:
For n-=1 state hydrogen energy level is split into three componets in the presence of external magnetic field. The energies are,
,
,

Here, E is the energy in the absence of electric field.
And
are the highest and the lowest energies.
The difference of these energies

is known as Bohr's magneton.
B=2.5 T,
Therefore,

Now,

Therefore, the energy difference between highest and lowest energy levels in presence of magnetic field is 

<u>Explanation</u>:
According to Newton's third law that each force has an equal and opposite reaction force in this case both of the jars will exert the same force an each other
. The force is given by

Where, F = force,
,
,
and Distance(r) = 0.42 m.
Substitute the values in the formula.




Answer:
In chemical compounds, atoms tends to have the electron configuration of a noble gas.
Explanation:
The noble gases are unreactive because of their electron configurations. This noble gas neon has the electron configuration of 1s22s22p6 . It has a full outer shell and cannot incorporate any more electrons into the valence shell.
The octet rule states that atoms tend to form compounds in ways that give them eight valence electrons and thus the electron configuration of a noble gas. An exception to an octet of electrons is in the case of the first noble gas, helium, which only has two valence electrons.