Integrated Concepts:. (a) Calculate the ratio of the highest to lowest frequencies of electromagnetic waves the eye can see, given the wavelength range of visible light is from 380 to 760 nm.
(b) Compare this with the ratio of highest (20,000 Hz) to lowest (20 Hz) frequencies the ear can hear.

a).  frequency = (speed) / (wavelength)

The speed of light is around 3 x 10⁸ m/s.

For 380 nm (violet light), frequency = (3 x 10⁸ m/s) / (380 x 10⁻⁹ m)

Frequency = 7.89 x 10¹⁴ Hz

For 760 nm (red light), frequency = (3 x 10⁸ m/s) / (760 x 10⁻⁹/s)

Frequency = 3.94 x 10¹⁴ Hz

The ratio is 2 .

That's 1 octave, or 0.3 of a decade.

b).  The ratio of highest/lowest sounds is (20,000 Hz/20 Hz) = 1,000

That's 3 decades, or about 10 octaves.

===> Speaking logarithmically ( ! ), ears are sensitive to a range of sound frequencies that's 10 times as wide as the range of light frequencies that eyes can detect.

that would be b i just took the test : )

a longitudinal wave moves energy that is to the direction of the wave’s movement. - true