As you may well know, placing metal objects inside a microwave oven can generate

Question

As you may well know, placing metal objects inside a microwave oven can generate sparks. Two of your friends am 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. In this problem, we will prove or disprove the latter idea using basic physics. Suppose the typical work function of the metal is roughly 4.380 times 10^-19 J. Calculate the maximum wavelength in angstroms of the radiation that will eject electrons from the metal. Considering that microwave ovens radiate at 2.45 GHz. how would you respond to the debate? The sparks cannot be caused by the photoelectric effect. The sparks could be caused by the photoelectric effect.

Explanation / Answer

Given energy = 4.380 x 10-19 J

We know,

E =hc/y

Here y is wavelength

y= 6.624 x 10-34 J. s x 3x108 m/s / (4.380 x 10-19 J)

= 4537 x 10-10 m

= 4537 Ao

(2)

Frequency = 2.45 x109 Hz

E= hv

here v is frequency

E = 6.624 x 10-34 J. s x 2.45 x109 Hz

= 1.62 x 10-24 J

Here this energy is less than work function of metal.

So, The sparks could not be caused by the photoelctric effect.

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