Answer:

Explanation:
The expression which represent the first diffraction minima by a circular aperture is given by
--------eqn 1
The angle through which the first minima is diffracted is given by
---------eqn 2
As
is very small so we can write 
So from eqn 1 and eqn 2 we can write
--------eqn 3
Here
is the position of first maxima D is the distance of screen from the circular aperture d is the diameter of aperture
It is given that diameter of circular aperture is 14.7 cm so 
Now putting all these value in eqn 3


The valence electrons increase as you move left to right.
Would presume you are asked to find the volume, since there is no second volume.
By General Gas Law:
P₁V₁/T₁ = P₂V₂/T₂
1.6 * 168 /255 = 1.3*V₂/285
V₂ = 1.6 * 168 * 285 / (1.3*255)
V₂ = 231.095
Final volume ≈ 231 cm³
Six.
If you want to double the force, you need to double either v or B. Changing the angle does not give totally predictable results. The formula is
F = q*v*B Sin(theta) altering theta isn't linear. Doubling B is. The answer is A
Seven
Seven is correct. The poles on a magnet is where the field is the strongest.
Eight
I can't really answer this question. Much depends on where you are and whether or not the readings are true or erratic. It is taking only one parameter into account where in reality there are many. My guess would be that as you move up the longitude the angle increases. So the answer would be near but not at the north pole. Seek out your notes for confirmation.