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# The red light emitted by a helium-neon laser has a wavelength of 632.8 nm. What is the frequency and energy per photon of that light?

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- Anonymous1 year agoFavorite Answer
Frequency = speed of light / wavelength

energy per mole = Avogadro's number * Planck's constant * speed of light / wavelength

- MyRankLv 611 months ago
Given,

Wavelength (λ) = 632.8nm

Speed of light (c) = 3 x 10⁸m/sec

Planck’s constant (h) = 6.626 x 10⁻³⁴J.sec

Frequency (f) = ?

Energy (E) = ?

We know that:-

Frequency (f) = speed of light (c) / wavelength (λ)

= 3 x 10⁸m/sec / 632.8 x 10⁹m

= 4.7 x 10⁻⁴/sec

= 4.7 x 10⁻⁴Hz

∴ frequency (f) = 4.7 x 10⁻⁴Hz

Now, Energy (E) = hf = 6.626 x 10⁻³⁴ x 4.7 x 10⁻⁴

= 31.14 x 10⁻³⁸

≈ 31 x 10⁻³⁸J

∴ Energy (E) = 31 x 10⁻³⁸J.

Source(s): https://myrank.co.in/

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