1. Frequency: 
The energy given is the energy per mole of particles:

1 mole contains a number of Avogadro of particles,
, equal to
particles
So, by setting the following proportion, we can calculate the energy of a single photon:

This is the energy of a single photon; now we can calculate its frequency by using the formula:

where
is the Planck's constant
f is the photon frequency
Solving for f, we find

2. Wavelength: 
The wavelength of the photon is given by the equation:

where

is the speed of the photon (the speed of light). Substituting,

Answer:
t_{out} =
t_{in}, t_{out} = 
Explanation:
This in a relative velocity exercise in one dimension,
let's start with the swimmer going downstream
its speed is

The subscripts are s for the swimmer, r for the river and g for the Earth
with the velocity constant we can use the relations of uniform motion
= D / 
D = v_{sg1} t_{out}
now let's analyze when the swimmer turns around and returns to the starting point

= D / 
D = v_{sg 2} t_{in}
with the distance is the same we can equalize

t_{out} = t_{in}
t_{out} =
t_{in}
This must be the answer since the return time is known. If you want to delete this time
t_{in}= D / 
we substitute
t_{out} = \frac{v_s - v_r}{v_s+v_r} ()
t_{out} = 
What object do you need to match
I believe it’s B. Electrons