Answer:
Frequency = 
Wavenumber = 
Energy = 
Energy = 1.4579 eV
Energy = 
Explanation:
As we are given the wavelength = 850 nm
conversion used : 
So, wavelength is 
The relation between frequency and wavelength is shown below as:

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


Wavenumber is the reciprocal of wavelength.
So,


Also,

where, h is Plank's constant having value as 
So,


Also,

So,


Also,

So,


Answer:
I would say technician A
Explanation:
Definition of voltage- An electromotive force or potential difference expressed in volts.
electromotive force is pressure so technician A would make sense.
Answer: blue
Explanation: blue cuz you look like somebody who likes blue