Finding the frequency and wavelength of an electromagnetic wave

[aChordate]

Homework Statement

Homework Equations

The Attempt at a Solution

Do I set up a proportion to first find the frequency of the electromagnetic wave in glass?

1.33/(3.42*10¹⁴)=1.62/f_glass= 4.17*10¹⁴

 

[Dick]

Homework Statement

View attachment 60137

Homework Equations

View attachment 60138

The Attempt at a Solution

View attachment 60138

Do I set up a proportion to first find the frequency of the electromagnetic wave in glass?

1.33/(3.42*10¹⁴)=1.62/f_glass= 4.17*10¹⁴

Put the equations aside for a minute and imagine your wave propagating from water into glass. Can the frequency change?

 

[aChordate]

I was wondering about that. I wouldn't think the frequency or the wavelength would change. Maybe it would just be slowed down??

 

[Dick]

I was wondering about that. I wouldn't think the frequency or the wavelength would change. Maybe it would just be slowed down??

Pick a point in the water and imagine you have 100 waves/sec passing by. Now pick a point in the glass. You must also have 100 waves/sec passing by, otherwise some waves are getting lost somewhere in between. Can't happen. Now tell me again what can change.

 

[aChordate]

So the frequency changes, but not the wavelength?

 

[Dick]

So the frequency changes, but not the wavelength?

That's sort of the opposite of what I was trying to convey. If 100 waves/sec go in one end then 100 waves/sec must come out the other end, otherwise something is eating waves in between. That's not the picture. I'm trying to convince you the frequency can't change. So two other things must change.

 

[aChordate]

Wavelength and velocity.

Glass would decrease the velocity and also decrease the wavelength (?)

 

[Dick]

Wavelength and velocity.

Glass would decrease the velocity and also decrease the wavelength (?)

Sure!