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Light of wavelength 589 nm in vacuum passes through a pie...

Light of wavelength 589 nm in vacuum passes through a piece of fused quartz of index of refraction n = 1.458. What is the frequency of the light in fused quartz?

[Speed of light c = 3.00×108ms1]

A.

5.09×1015Hz

B.

5.09×1014 Hz

C.

1.77×1015 Hz

D.

1.77×1014 Hz

Correct answer is B

n=1.458, c=3.00×108ms1 ,λo = 589nm;  f=?

Speed of light in a medium (v)=cn  where n is the refractive index of the medium

⇒λn=5891.458 = 404nm

  v=fλ
  
⇒f=\frac{v}{λ} 

=\frac{2.06×10^8}{404×10^-9} 1nano=10^{-9}

∴f=5.09×10^{14} Hz