Answer:
Its speed decreases to 2.26 x 10^8 m/s , and its wavelength decreases by a factor of 1.33.
Step-by-step explanation:
When beam of light travel from a less dense medium (air) to more dense medium (water), the speed of the light decreases.
Refractive index of water = speed of light in air / speed of light in water
Refractive index of water = 1.33
speed of light in air = 300,000,000 m/s
Thus, speed of light in water = (300,000,000) / 1.33
= 2.26 x 10^8 m/s
From simple wave equation;
Speed of wave = frequency x wavelength.
From the equation above, at a constant frequency, as speed decreases, wavelength also decreases. In this question the speed decreased by a factor of 1.33, therefore the wavelength will also decrease by a factor of 1.33.
Therefore, Its speed decreases to 2.26 x 10^8 m/s , and its wavelength decreases by a factor of 1.33.