Answer:
Wavelength is calculated as 213.9 nm
Solution:
As per the question:
Wavelength of light = 570 nm
Time, t = 16.5 ns
Thickness of glass slab, d = 0.865 ns
Time taken to travel from laser to the photocell, t' = 21.3
Speed of light in vacuum, c = 
Now,
To calculate the wavelength of light inside the glass:
After the insertion of the glass slab into the beam, the extra time taken by light to cover a thickness t = 0.865 m is:
t' - t = 21.3 - 16.5 = 4.8 ns
Thus


where
n = refractive index of the medium
v = speed of light in medium


n = 2.66
Now,
The wavelength in the glass:


I think the correct answer from the choices listed above is option B. It is the electrons that flow because of electrical attraction and repulsion causes an electric current in a wire. Electrons, which continuously move in wire, are called Electric Current. Hope this answers the question.
Answer:
Reflection involves a change in direction of waves when they bounce off a barrier. Refraction of waves involves a change in the direction of waves as they pass from one medium to another.
Explanation:
Answer:
A. The wavelength doubles but the wave speed is unchanged
Explanation:
The relationship between the period and wavelength is direct. Doubling the period of the oscillator will correspondingly double the wavelength but the wave speed is unaffected