The expected outcome would be A. The reaction will speed up after adding a catalyst to a chemical reaction.
Answer: a) 
b) 
Explanation: Visible light is a form of electromagnetic wave.
Wavelength is defined as the distance between two successive crests of a wave. It is represented as symbol
.
Frequency is defined as the number of complete cycles happening per second. It is represented by the symbol
.
Wavelength and Frequency follow inverse relation,

where, c = speed of light = 
Wavelength and frequency of a wave is usually expressed in a range.
a) 
b) 
If you are talking about chemistry, it's coefficient!
In a crystal, the molecules are closer together as they are in any solid. they have less room to move, and might even be combined together rather than individual