Find the range of frequency of light that is visible to an average human being `(400nmltlamdalt700nm)`

The wavelength range of the light that is visible to an average human being is 400 nm to 700 nm . What is the frequency range of this visile light ?

What is the range of frequencies of visible light ?

Write range of frequencies of visible light.

What is the lowest limit of frequency range that is audible to human beings ?