Answer: Option (b) is the correct answer.
Explanation:
It is known that when a ray of light tends to travel from a denser to rarer medium then there occurs total internal reflection.
For a denser medium the refractive index is greater than that of a rarer medium. This means that for the given situation refractive index of medium 
is greater than medium 
.
this also means that incident angle must be greater than the critical angle of the medium.
Thus, we can conclude that the statement > must be true for total internal reflection to occur.
Answer:
hydrogen
Explanation:
pH is a measure of the ion concentration of hydrogen in a solution.
In chemistry, it literally means power of hydrogen ions and it is a measure of the molar concentration of hydrogen ions in a particular solution, thus specifying the acidity, neutrality or basicity of chemical solutions.
Mathematically, the pH of a solution is given by ![pH = -log 10[H^{+}]](https://tex.z-dn.net/?f=pH%20%3D%20-log%2010%5BH%5E%7B%2B%7D%5D)
Hence, a solution with a pH of 7 is neutral.
Also, a solution with a pH below 7 is acidic but basic if it's pH is above 7.
