A laser beam is incident at an angle of 29.8° to the vertical onto a solution of corn syrup in water. (a) If the beam is refracted to 18.62° to the vertical, what is the index of refraction of the syrup solution? (b) Suppose the light is red, with wavelength 632.8 nm in a vacuum. Find its wavelength in the solution.

Respuesta :

Answer:

(a) 1.5

(b) [tex]421.86 * 10^{-9} m[/tex]

Explanation:

Angle of incidence, [tex]i[/tex] = 29.8°

Angle of refraction, [tex]r[/tex] = 18.62°

(a) Index of refraction is given as:

[tex]n = \frac{sin(i)}{sin(r)}[/tex]

[tex]n = \frac{sin(29.8)}{sin(18.62)} \\\\\\n = \frac{0.4970}{0.3193} \\\\\\n = 1.5[/tex]

The refractive index of the syrup is 1.5.

(b) Wavelength of the red light in a vacuum, λ(1)  = [tex]632.8 nm = 632.8 * 10^{-9} m[/tex]

Refractive index is also a ratio of the speed of the light in a vacuum with the speed of light in a particular medium:

[tex]n = \frac{c}{v}[/tex]

The speed of light in a vacuum is given as;

c = λ(1) * f

=> f = c/λ(1)

The speed of light in a medium is given as;

v = λ(2) * f

=> f = v/λ(2)

(λ = wavelength and f = frequency)

We know that the frequency of light does not change when it changes media, hence, we can equate both frequencies:

c/λ(1) = v/λ(2)

Therefore:

c / v = λ(1) / λ(2)

Therefore, refractive index will become:

n = λ(1) / λ(2)

=> 1.5 =  [tex]632.8 * 10^{-9}[/tex] / λ(2)

The wavelength of the red light in the solution is therefore:

λ(2) = [tex]632.8 * 10^{-9}[/tex] / 1.5

λ(2) = [tex]421.86 * 10^{-9} m[/tex]

The wavelength of the light in the solution is [tex]421.86 * 10^{-9} m[/tex]

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