The answer is C Hydroelectric
Answer:

Explanation:
When an electromagnetic wave passes through the interface between two mediums, it undergoes refraction, which means that it bents and its speed and its wavelength change.
In particular, the wavelength of an electromagnetic wave in a certain medium is related to the index of refraction of the medium by:

where
is the wavelength in a vacuum (air is a good approximation of vacuum)
n is the refractive index of the medium
In this problem:
is the original wavelength of the wave
n = 1.47 is the index of refraction of corn oil
Therefore, the wavelength of the electromagnetic wave in corn oil is:

Answer:
Velocity, v = 0.239 m/s
Explanation:
Given that,
The distance between two consecutive nodes of a standing wave is 20.9 cm = 0.209 m
The hand generating the pulses moves up and down through a complete cycle 2.57 times every 4.47 s.
For a standing wave, the distance between two consecutive nodes is equal to half of the wavelength.

Frequency is number of cycles per unit time.

Now we can find the velocity of the wave.
Velocity = frequency × wavelength
v = 0.574 × 0.418
v = 0.239 m/s
So, the velocity of the wave is 0.239 m/s.
The monomer of glucose makes up all carbohydrates