Easy physics question I am sure

Finns14

Golden Member
Oct 6, 2005
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How do you calculate velocity of la wave when given wavelengthn and frequency. In nm and Hz respectivly.
 

mugs

Lifer
Apr 29, 2003
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multiply them?

That would give you the answer in nm/s I believe

wavelength = nm/cycle
hz = cycles/second

Multiply and cancel out cycles, you end up with nm/s
 

MrDudeMan

Lifer
Jan 15, 2001
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what media? in a vacuum every wave propogates at c, but that isnt true in different media. for example, electrons travel faster in water than light given certain circumstances. c = f * lambda in a vacuum, but im not sure how to calculate propogation velocity off of the top of my head for non vacuum transmission.
 

Finns14

Golden Member
Oct 6, 2005
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Sorry need it in m/s but that can be done with simple 10x scale but I am pretty sure 1Hz doesn't equal 1s.

Edit I need this to calcualte index of refraction which I know how to do once I calculate v
 

MrDudeMan

Lifer
Jan 15, 2001
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Originally posted by: Finns14
Sorry need it in m/s but that can be done with simple 10x scale but I am pretty sure 1Hz doesn't equal 1s.

1 Hz equals 1 cycle per second. period is 1 over the frequency, so if your frequency is 1 Hz your period is 1 s. to go from nm to m just multiply by 10^9.

edit: another example...if the frequency is 10Hz, your period is .1 s, and so on.
 

Eeezee

Diamond Member
Jul 23, 2005
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v = f*lambda.

It's nifty to remember that light waves have a constant frequency when traversing different mediums, so c = f*lambda in vacuum and the velocity/wavelength decrease as you go into different mediums.
 

Eeezee

Diamond Member
Jul 23, 2005
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If you want m/s from nanometers and Hz, then v = (wavelength * 10^-9)*(frequency)