Comparing Compton Effect: 10pm vs 20pm Wavelengths for Electromagnetic Waves

[asdf1]

for the following question:
for electromagnetic waves A of wavelength 10pm and electromagnetic waves B o f wavelengthh 20 pm, which produces more pronounced Compton effect?

my problem:
the question doesn't give the scattering angle or final wavelength, so isn't this question too ambiguous?

 

[Tide]

The final wavelength depends on the scattering angle so why not compare how they each scatter from a given particle starting at rest?

 

[asdf1]

can you explain what do you mean by that?

 

[Tide]

The change in wavelength in Compton scattering is:

$$\Delta \lambda = \frac {h}{m_e c} \left( 1 - \cos \theta \right)$$

where $\theta$ is the scattering angle. You can use that to compare the change in energy of the photons to determine which produces a "more pronounced Compton effect."

 

[asdf1]

but delta lamda and cos(cita) are both variables!

 

[Tide]

Indeed they are! So, follow my suggestion to get your answer.

 

[asdf1]

maybe my english isn't too good~
i still don't understand what you mean...
@@a

 

[Astronuc]

How about - the greater the photon energy, i.e. shorter the wavelength, the more momentum the photon has - p = E/c.

Think of conservation of momenutm and energy.

 

[asdf1]

@@a
i thought you also had to consider what type of material it hits, because doesn't compton effect has a range?

 

[Tide]

Your original question was which photon produces a more pronounced Compton effect? Logically, you will keep all other variables the same and only consider what effect the wavelength has on the scattering.

 

[asdf1]

i see... so that would be B wavelength produces the more pronouced Compton effect right?

 

[Tide]

No. The shorter wavelength will produce a more pronounced effect -- BUT -- you have to SHOW it! E.g. calculate how much energy is transferred to the charged particle. You have the basic relations here so you should be able to do that.

 

[asdf1]

ok, i get it! thanks! :)