Calculate the energy (J) increase due to heating.
Then:
Use energy per photon = h f = (Planck's constant)(frequency)
frequency = (speed of light)/(wavelength)
Divide: energy gain/energy per photon = number of photons
Answer:
370.6 nm
Explanation:
wavelength in vacuum = 494 nm
refractive index of water with respect to air = 1.333
Let the wavelength of light in water is λ.
The frequency of the light remains same but the speed and the wavelength is changed as the light passes from one medium to another.
By using the definition of refractive index

where, n be the refractive index of water with respect to air
By substituting the values, we get

λ = 370.6 nm
Thus, the wavelength of light in water is 370.6 nm.
The answer might be B i hope is helps
The answer is 7 (its like the only question thats easy so far lol)