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 friends are arguing over the cause of the sparking, with one stating that the microwaves "herd" elect 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 will prove or disprove the latter idea using basic physics. Suppose the typical work function of the metal is roughly 4.790 * 10^19. 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.s

Explanation / Answer

1) we know that

E = h x c / lamda

so

lamda = h x c / E

so

lamda = 6.626 x 10-34 x 3 x 10^8 / 4.79 x 10-19

lamda = 4.15 x 10-7

so

the maximum wavelength is 4.15 x 10-7 m = 4150 A

2)

now

we know that

f = c / lamda

so

lamda = c / f

lamda = 3 x 10^8 / 2.45 x 10^9

lamda = 0.122 m

but

the max wave length that can ejected by oven is 4150 A

so

the sparks cannot be caused by the photoelectric effect

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.