Answer:
(a)
(b) ![\theta = 85.44^{\circ}](https://tex.z-dn.net/?f=%5Ctheta%20%3D%2085.44%5E%7B%5Ccirc%7D)
Solution:
As per the question:
Side of the cube, a = 4.4 cm
Coordinates of the diagonally opposite corner, A = <4.4, 4.4, 4.4> cm
Now,
(a) To calculate the unit vector:
(b) To calculate the angle between the two vectors say A and A' is given by:
(1)
Now,
The coordinates of the diagonally opposite corner, A' is <0, 0, 1> cm
Thus
Now,
Using equation (1) :
![\theta = cos^{- 1}(\frac{(\frac{\hat{i} + \hat{j} + \hat{k}}{\sqrt{3}})\cdot \hat{k}}{|A||A'|})](https://tex.z-dn.net/?f=%5Ctheta%20%3D%20cos%5E%7B-%201%7D%28%5Cfrac%7B%28%5Cfrac%7B%5Chat%7Bi%7D%20%2B%20%5Chat%7Bj%7D%20%2B%20%5Chat%7Bk%7D%7D%7B%5Csqrt%7B3%7D%7D%29%5Ccdot%20%5Chat%7Bk%7D%7D%7B%7CA%7C%7CA%27%7C%7D%29)
![|A||A'| = (\sqrt{4.4^{2} +4.4^{2} + 4.4^{2}})(\sqrt{0^{2} + 0^{2} + 0^{2}}) = 7.261](https://tex.z-dn.net/?f=%7CA%7C%7CA%27%7C%20%3D%20%28%5Csqrt%7B4.4%5E%7B2%7D%20%2B4.4%5E%7B2%7D%20%2B%204.4%5E%7B2%7D%7D%29%28%5Csqrt%7B0%5E%7B2%7D%20%2B%200%5E%7B2%7D%20%2B%200%5E%7B2%7D%7D%29%20%3D%207.261)
Thus
![\theta = cos^{- 1}(\frac{\frac{1}{\sqrt{3}}}{7.261})](https://tex.z-dn.net/?f=%5Ctheta%20%3D%20cos%5E%7B-%201%7D%28%5Cfrac%7B%5Cfrac%7B1%7D%7B%5Csqrt%7B3%7D%7D%7D%7B7.261%7D%29)
![\theta = cos^{- 1}(0.07946) = 85.44^{\circ}](https://tex.z-dn.net/?f=%5Ctheta%20%3D%20cos%5E%7B-%201%7D%280.07946%29%20%3D%2085.44%5E%7B%5Ccirc%7D)
Answer
From the question we can see that the in medium 1 speed of light is 200,000 Km/s where as in Medium 2 speed of light is 250,000 km/s.
We can conclude that medium 1 is denser than Medium 2.
In third medium Light speed halts so, the third medium is opaque.
We can say that
Medium 1 can be either water, glass.
Medium 2 will be gas
Medium 3 will be an opaque material.
There is no certain time on how long it takes. Because the factors will always be different and the factors heavily affect the evaporation time. Some factors include: humidity, heat, how the sun is visible (whether clouds are covering it or not)