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The red light emitted by a He-Ne laser has a wavelength of 633 nm in air and travels at...

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happyface22 | Student, Grade 11 | Honors

Posted February 11, 2012 at 10:07 AM via web

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The red light emitted by a He-Ne laser has a wavelength of 633 nm in air and travels at 3.00 × 10^8 m/s. Find the frequency of the laser light.

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justaguide | College Teacher | (Level 2) Distinguished Educator

Posted February 11, 2012 at 10:55 AM (Answer #1)

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Any wave has three parameters, the velocity of the wave v, the frequency of the wave f and the wavelength w. These are related to each other by the relation v = w*f

The red-light of the He-Ne laser has a velocity 3*10^8 m/s. Its wavelength is 633 nm or 633*10^-9 m.

If the frequency of the wave is f, 3*10^8 = 633*10^-9*f

=> f = 3*10^8/633*10^-9 Hz

=> f = 4.739*10^14 Hz

The required frequency of the light emitted by the He-Ne laser is 4.739*10^14 Hz.

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Jyotsana | TA , Grade 10 | Valedictorian

Posted February 21, 2014 at 11:28 PM (Answer #2)

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speed= 3.0*10^8m/s

wavelength=633nm  You have to change the unit nm to m

To do that you have to multiply by 10^-9

633*10^-9=6.33*10^-7m

Frequency=Speed/Wavelength

(3.0*10^8)/(6.33*10^-7)

Frequency= 4.7*10^14Hz

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