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When sufficiently high frequency light hits a metal surface it emits electrons. Now what will happen if the light is coming through two slits and forming an interference pattern similar to the double-slit experiment on the metal surface? Will the metal surface emit electrons or not?

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It will emit electrons according to where photons in the interference pattern hit.

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Bright spots in the pattern are where almost all photons hit, dark spots in the pattern are where almost no photons hit. The emission will occur in the bright areas.

In double slit interference the classical explanations implied photons were hitting in the dark areas but cancelling each other out (which is a violation of conservation of energy). The modern understanding is the photon wave function which has highly probable paths (causing bright areas) that the photons follow. A requirement of a the photon path is that its length is a multiple of its wavelength.

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  • $\begingroup$ Will you please elaborate it? The photons are acting like waves here - they are forming an interference pattern on the metal surface. How can waves eject out electrons? $\endgroup$ – White Milkybar Oct 22 at 1:28
  • $\begingroup$ @WhiteMilkybar The answer is correct. What happens between the emission and the absorption (on the screen) may be described from different people in different way, it is unprovable. To calculate the fringes you use the interference picture. But in a closer view it is obvious that the photons get deflected from the edges and are concentrated in the bright areas. No annihilation of two photons in the dark area. $\endgroup$ – HolgerFiedler Oct 22 at 5:24
  • $\begingroup$ @WhiteMilkybar - The term 'interference' is historical and misleading but it is still taught today in high school and in early university courses. The interference explanation does work mathematically in many situations (double slit approximation, thin film interference). Ultimately it falls short as in single photon experiments where we realize there are no photons or no energy in the dark areas. The interference explanation is convenient and as well was the norm in the early days of physics .... early 1900s. Interference violates conservation of energy for photons. $\endgroup$ – PhysicsDave Oct 22 at 22:16
  • $\begingroup$ You are posting the exact same answer for a whole bunch of different questions, independent of what was actually asked. $\endgroup$ – Peter Shor Oct 22 at 22:21
  • $\begingroup$ @PeterShor - The term 'interference' is historical and misleading but it is still taught today in high school and in early university courses. The interference explanation does work mathematically in many situations (double slit approximation, thin film interference). Ultimately it falls short as in single photon experiments where we realize there are no photons or no energy in the dark areas. The interference explanation is convenient and as well was the norm in the early days of physics .... early 1900s. Interference violates conservation of energy for photons. $\endgroup$ – PhysicsDave Oct 22 at 22:22

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