Answer:
Technician A
Explanation:
Galvanic corrosion is not on only one metal alone but caused when two metals are interacting. Thus, Duplicating the original installation method is a better option because re-using a coated bolt doesn't prevent galvanic corrosion because both materials must be coated and not just the bolt and in technician B's case he is coating just the bolt. Thus, technician B's method will not achieve prevention of galvanic corrosion but technician A's method will achieve it.
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:
= -0.303 KW
Explanation:
This is the case of unsteady flow process because properties are changing with time.
From first law of thermodynamics for unsteady flow process

Given that tank is insulated so
and no mass is leaving so

Mass conservation 
is the initial and final mass in the system respectively.
Initially tank is evacuated so 
We know that for air
,

So now putting values

= -0.303 KW