Answer:
Correct option is A - The force of kinetic friction is smaller than that of static friction, but Fg remains the same.
Explanation:
(A) The force of kinetic friction is smaller than that of static friction, but Fg remains the same
Answer:

Explanation:
By Snell's law we know at the left surface




now we have


now on the other surface we know that
angle of incidence = 

so again we have

so we have


also we know that


By solving above equation we have

The easiest way to answer this question is just to get the answer first. The answer is A with the added comment that no chemical reaction has taken place.
Layered means that the chemicals are not soluble in one another. B is not the answer.
C is eliminated by what what was said about A.
D a solution is not a pure substance (singular) by itself. There are at least 2 chemicals together.
Answer:
Electrical force, F = 90 N
Explanation:
It is given that,
Charge on sphere 1, 
Charge on sphere 2, 
Distance between two spheres, d = 6 cm = 0.06 m
Let F is the electrical force between them. It is given by the formula of electric force which is directly proportional to the product of charges and inversely proportional to the square of distance between them such that,


F = 90 N
So, the electrical force between them is 90 N. Hence, this is the required solution.