## frequencies and wavelength

$c=\lambda v$

Anjali_Kumar1F
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Joined: Fri Sep 28, 2018 12:25 am

### frequencies and wavelength

Can some explain me how to do this question step by step it is from the 6th edition.

1.7 (a) The frequency of violet light is 7.1 x10^14 Hz. What is the wavelength (in nanometers) of violet light? (b) When an electron beam strikes a block of copper, x-rays with a frequency of 2.0 x 10^18 Hz are emitted. What is the wavelength (in picometers) of these x-rays?

Chem_Mod
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### Re: frequencies and wavelength

For both part a and part b you can use the equation speed of light = wavelength * frequency.

Chem_Mod
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### Re: frequencies and wavelength

For part (a), we are looking for the wavelength, and we are only given the frequency. We can use the relationship that the speed of light $c = \nu \lambda$
We know that the speed of light is $3.00*10^{8}m/s$.
Plug this in for c and plug in the known value of frequency for v.
Once you solve for wavelength $\lambda$, it will be given in meters due to the units of the other parameters.
Knowing that $1*10^{-9}m = 1nm$, you can then convert the wavelength into the desired units of nm.

For part (b), you can follow the same steps as for part (a).
Use the formula $c = \nu \lambda$ to solve for the wavelength.
In this problem, it asks for the answer to be given in picometers.
You can use the conversion rate that $1*10^{-12}m = 1pm$ to put your answer in the right units.

I hope this gives you some more guidance to solve this kind of problem!

Anjali_Kumar1F
Posts: 62
Joined: Fri Sep 28, 2018 12:25 am

### Re: frequencies and wavelength

In the formula E=hv what does the letter v respresent? I know E is energy and h is a given number which is the constant but what is v.

inlovewithchemistry
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Joined: Fri Sep 28, 2018 12:19 am

### Re: frequencies and wavelength

V represents the velocity of the object.

inlovewithchemistry
Posts: 104
Joined: Fri Sep 28, 2018 12:19 am

### Re: frequencies and wavelength

Anjali_Kumar3E wrote:In the formula E=hv what does the letter v respresent? I know E is energy and h is a given number which is the constant but what is v.

V represents velocity of the particle.