What is the frequency of red light with a wavelength of 645 nm?

4.64E14

Explanation:

First convert 645 nm to m = 6.4500E-7m. The equation for finding v with these values is the speed of light/wavelength. so 2.998E8/6.4500E-7m.

so your v or frequency would equal 4.64E14

Fun fact you know this is visible light because the visible light range is within the E14 range.

a  solution  is always transparent, light passes through with no scattering from solute particles which are molecule in size. the  solution  is homogeneous and does not settle out. a colloid is intermediate between asolution  and a  suspension. while asuspension  will separate out a colloid will not.

a corroding iron, if that's one of your choices