Does Frequency Change in a Medium?

AI Thread Summary
When light enters a different medium, its wave speed and wavelength change, but its frequency remains constant, as stated by a physics lecturer. The formula c = fλ indicates that while wave speed (c) and wavelength (λ) can vary, frequency (f) must stay the same to conserve energy. The discussion emphasizes that at the interface of two media, the frequency of the wave does not change, aligning with the principle of energy conservation. Participants acknowledge that rearranging the formula supports the idea that frequency remains constant despite changes in speed and wavelength. The consensus confirms that the lecturer's explanation is correct.
Theudius
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Hi I was told by physics lecturer that both the wave speed and wave length of light changes when it enters a medium, however I questioned this stating that if both wave speed and wave length changed then frequency must also according to the formula c = fλ. He stated that "frequency is energy and energy is conserved"

I was wondering if I would be able to get a more in depth answer from someone here and correct my lecturers statement.
 
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No joy: teacher is right. You can convince yourself easily if you think of the conditions at the interface. If the one 'vibrates' at a certain frequency, then the other won't 'vibrate' at a different frequency
 
Theudius said:
however I questioned this stating that if both wave speed and wave length changed then frequency must also according to the formula c = fλ.

BvU said:
No joy: teacher is right. You can convince yourself easily if you think of the conditions at the interface. If the one 'vibrates' at a certain frequency, then the other won't 'vibrate' at a different frequency

indeed

@Theud try rearranging your formula and fix the frequency so f = c/λ ... you can have any number of variations of c and λ and have the same frequency

Dave
 
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You mean the same frequency.
 
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pixel said:
You mean the same frequency.

oops corrected :rolleyes:
 

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