Question

how do the the following quantities change speed wavelength frequency amplitude second medium is denser than the first medium

Answer 1

Given:

A electromagnetic wave (light) travels from optically rarer to optically denser medium.

To find:

Change in

• Speed
• Wavelength
• Frequency

Solution:

Let us consider that light travels from air (rarer medium) to glass (denser medium):

$\therefore \: v_{glass} = \dfrac{ v_{air} }{ \mu_{glass} }$

$\implies\: v_{glass} = \dfrac{ v }{ \mu_{glass} }$

Since $\mu_{glass}$ > 1 , hence the velocity of light in glass will be lesser than that of air.

$\implies\: v_{glass} < v$

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Since frequency is determined by the source of the sound , even after refraction at the interface, the frequency will remain same.

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Wavelength can be written as:

$\therefore \: v_{glass} = \dfrac{ v_{air} }{ \mu_{glass} }$

$\implies\: f \times \lambda_{glass} = \dfrac{ f \times \lambda_{air} }{ \mu_{glass} }$

$\implies\: \lambda_{glass} = \dfrac{ \lambda_{air} }{ \mu_{glass} }$

$\implies\: \lambda_{glass} < \lambda_{air}$

So, wavelength will also decrease.