Key concepts
Density
Mass
Volume
Concentration
Buoyancy
Water
Answer :
(a) The energy of blue light (in eV) is 2.77 eV
(b) The wavelength of blue light is 
Explanation:
The relation between the energy and frequency is:

where,
h = Plank's constant = 
Given :
Frequency = 
Conversion used :

So,


Also,

So,


The energy of blue light (in eV) is 2.77 eV
The relation between frequency and wavelength is shown below as:

Where,
c = the speed of light = 
Frequency = 
So, Wavelength is:


Conversion used : 
The wavelength of blue light is 
Answer:
1 unit
Explanation:
It is expressed as a multiple of one-twelfth the mass of the carbon-12 atom, 1.992646547 × 10−23 gram, which is assigned an atomic mass of 12 units.
1/12 * 12 = 1. I think so.
If that is your picture, then the answer is that
Geometry A is trigonal planarand Geometry B is trigonal pyramidal