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Find the frequency in terahertz of visible light with a wavelength of 639 nm in vacuum.

1 Answer

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The relationship between frequency and wavelength for electromagnetic waves is

f= (c)/(\lambda)
where
f is the frequency
c is the speed of light

\lambda is the wavelength

For the light in our problem, the wavelength is

\lambda=639 nm= 6.39 \cdot 10^(-7) m

and with the previous equation we can find the corresponding frequency:

f= (c)/(\lambda)= (3 \cdot 10^8 m/s)/(6.39 \cdot 10^(-7) m)=4.69 \cdot 10^(14)Hz
And since
1 THz = 10^(12) Hz, the frequency can be rewritten as

f=4.69 \cdot 10^2 THz
User KawaLo
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