The wavelength range of the visible spectrum extends from violet (400 nm) to red (750 nm). Express these wavelength in frequencies (Hz). (1 nm = 10−9 m).
4×1014 to 7.5×1014Hz
We know that,
v=cλ
Now, frequency of violet light is:
v=cλ=3.00×108ms−1400×10−9m=7.50×1014Hz
Frequency of red light is:
v=cλ=3.00×108ms−1750×10−9m=4.00×1014Hz
The range of visible spectrum is from 4.0×1014Hz in terms of frequency units.