sapling problem

[Hana Sigsbee 3B]

"As you may well know, placing metal objects inside a microwave oven can generate sparks. Two of your friends are arguing over the cause of the sparking, with one stating that the microwaves "herd" electrons into "pointy" areas of the metal object, from which the electrons jump from one part of the object to another. The other friend says that the sparks are caused by the photoelectric effect. Prove or disprove the latter idea using basic physics.

Suppose the typical work function of the metal is roughly 5.010×10−19 J. Calculate the maximum wavelength in angstroms of the radiation that will eject electrons from the metal."

[Astha Patel 2J]

Someone had asked this a couple weeks ago and this was my reasoning:

So the problem gives the energy requried to remove an electron. In this problem, the work function should equal the energy of the incoming photon, so hv= work function. Substitute frequency for c/lamda so that you can solve for wavelength. This gives you the answer to the first part. For the second part of the question, the photoelectric effect only makes sense if the wavelength that you solved for in part 1 is similar to the wavelength due to the frequency that the microwave radiates at in the problem. Convert the frequency of the microwave (remember that GHz means giga hertz), and use c=lamda*v to solve for wavelength. If the wavelengths are different, then the sparks can't be due to the photoelectric effect.
Hope this helps :)

[Kainalu Puu-Robinson]

Also, dont forget to divide by 1x10^-10 (1A) on the last step since you're original answer is in meters. I ran into this problem when solving this question, hope this helps!