Question

Activity 26-3. Compton scattering [Accompanies Section 26-3] In Compton scattering a photon collides with an electron that is initially at rest. (a) Rank the following quantities in order from largest to smallest. If any two quantities are the same, state this. Explain how you made your ranking. (i) The wavelength of an x-ray photon (ii) The change in wavelength of an x-ray photon in Compton scattering when it scatters through an angle of 0° (that is, the photon continues in the same direction as its initial motion) (iii) The change in wavelength of an x-ray photon in Compton scattering when it scatters through an angle of 90° (that is, the photon is scattered in a direction at right angles to its initial motion) (iv) The change in wavelength of an x-ray photon in Compton scattering when it scatters through an angle of 180° (that is, the photon is scattered in the direction opposite to its initial motion) (b) Fill in the blanks in each of the following statements with the word increases, the word decreases, the phrase stays the same, or the phrase don't know. (i) In Compton scattering if the angle through which the photon is scattered increases, the energy of the scattered photon the momentum of the scattered photon the frequency of the scattered photon and the speed of the scattered photon (ii) In Compton scattering if the angle through which the photon is scattered increases, the kinetic energy of the scattered electron the momentum of the scattered electron _, and the speed of the scattered electron

Answer 1

(a) The wavelength of x rays ranges in between 10^-8 and 10^-12 m

The change in wavelength in a compton experiment depends on the scattering angle:

$\Delta \lambda =\frac{h}{mc}(1-\cos \theta )$

0=

$\Delta \lambda =0$

$\theta =90^{\circ}$

$\Delta \lambda =\frac{h}{mc}=2.4\times 10^{-12}m$

$\theta =180^{\circ}$

$\Delta \lambda =2\frac{h}{mc}=4.8\times 10^{-12}m$

So the ranking from largest to smallest would be iiviiiii

(b) i. In Compton scattering if the angle through wich the photon is scattered increases, the energy of the scattered photon decreases, the momentum of the scattered photon decreases, the frequency of the scattered photon decreases and the speed of the scattered photon remains the same

ii. In Compton scattering if the angle through wich the photon is scattered increases, the kinetic energy of the scattered electron increases, the momentuum of the scattered electron increases and the speed of the scattered electron increases