Answer: 799.447 Hz (799.447 s^-1)
Step-by-step explanation:
Recall that Wavelenght=wave speed/frequency.
Let frequency be f, wavelenght w, and wave speed be v.
Rearrange:
w=v/f
fw=v
f=v/w
For simplicity, the speed of light is c.
Substitute:
f=c/(3.75*10^5)
f=799.446555... ≈ 799.447
Check with units:
s^-1=m/s * 1/m
s^-1=m/(sm)
s^-1=1/s
s^-1=s^-1