The beam from an argon laser (of wavelength 515 nm) has a diameter d of 3.00 mm and a continuous energy output rate of 5.00W. The beam is focused onto a diffuse surface by a lens whose focal length f is 3.50 cm. A diffraction pattern such as that of Fig. 36-10 is formed, the radius of the central disk being given by

(see Eq. 36-12 and Fig. 36-14).The central disk can be shown to contain 84% of the incident power.
(a) What is the radius of the central disk?
(b) What is the average intensity (power per unit area) in the incident beam?
(c) What is the average intensity in the central disk?

Transcribed Image Text:

R-12 1.22/λ Low energy High energy Spin down Spin up T Ko-AK 0 Target atom Ko Incident electron -rav photon