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 = \(3.00×10^8 ms^{-1}\)]
A
\(5.09×10^{15}\)Hz
B
\(5.09×10^{14}\) Hz
C
\(1.77×10^{15}\) Hz
D
\(1.77×10^{14}\) Hz
Verified Correct Answer: B.
Physical Principles & Numerical Solution
n=1.458, c=\(3.00 \times10^8 ms^-1\) ,\lambdao = 589nm; f=?
Speed of light in a medium (v)=\(\frac{c}{n}\) where n is the refractive index of the medium
⇒\lambdan=\(\frac{589}{1.458}\) = 404nm
v=f\lambda
⇒f=\(\frac{v}{\lambda}\)
=\(\frac{2.06\times10^8}{404\times10^-9}\) \(1nano=10^{-9}\)
∴f=\(5.09\times10^{14}\) Hz
Source: WAEC / JAMB / NECO Classroom Archive (Record #67912)