Light bulb in a microvawe oven

In summary: Dave put the light bulb in, the light bulb lit up. So Dave concluded that the microwave oven was causing the current to flow through the light bulb. However, another student disagreed with Dave, and said that the current couldn't be flowing through the light bulb because microwaves don't create currents. So which is correct?
  • #1
physnewbie
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I'm sorry to reopen the debate on what happens when I put a light bulb in a microvawe oven, but the question is driving me crazy.
I'm debating with other students about "why I light bulb lights up when I put it in a microwave oven ?".
I read the old thread posted in 2003 https://www.physicsforums.com/threads/light-bulb-in-a-microwave.6438 - I found a lot of nice conclusions about, but some of them are in contradiction.
Duncan states that "The incandescent bulb is likely to be lit due to current in the filament set up by the microwaves directly. Microwaves waves applied to metals will in general create electric currents".
But chroot objects by stating that "Microwaves applied to metals do not create currents. Furthermore, your assertion that the arcing due to foil is caused by such currents is also wrong" (and I agree with him).
Can anyone put the "end" word to this question by explaining why the light bulb lights up ?
Many thanks in advice.
 
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  • #2
Why should an EM wave not cause currents to flow in a conductor? It works for lower radio frequencies. A typical lamp filament and supporting wires is pretty much the same size as the wavelength of around 12cm and it can be near resonance, which can cause the induced currents to be high. Once the (very thin) filament gets hot, the gas around it can also get excited and become ionised due to the high temperature and EM fields. Then the whole bulb can be filled with attractive looking wavy arcs. You have several hundred Watts of microwave power available and the filament may only be designed to handle, say 60W so it will glow at a much higher temperature than it would normally do.
 
  • #3
physnewbie said:
But chroot objects by stating that "Microwaves applied to metals do not create currents. Furthermore, your assertion that the arcing due to foil is caused by such currents is also wrong" (and I agree with him).

which is completely incorrectIf that were the case, then we couldn't/wouldn't have microwave radio transmitters/receivers for communications
Your satellite TV ( if you have it) comes to you via a microwave transmitter on the satellite. That microwave radio signal generates/induces currents
in the antenna that is part of the dish antenna at your/your neighbour's homeDave
 
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FAQ: Light bulb in a microvawe oven

1. How does a light bulb work in a microwave oven?

A light bulb in a microwave oven works by using a filament, similar to a traditional light bulb, that heats up when electricity passes through it. This heat is then converted into light, allowing you to see inside the microwave.

2. What is the purpose of a light bulb in a microwave oven?

The main purpose of a light bulb in a microwave oven is to allow you to see the food while it is cooking. It also helps you monitor the progress of your food and check for any potential issues, such as spills or overcooking.

3. Can I use any type of light bulb in a microwave oven?

No, it is important to use a specific type of light bulb that is designed for use in a microwave oven. These bulbs are made of heat-resistant materials and can withstand the high temperatures and vibrations inside the microwave.

4. Why does the light bulb in my microwave oven sometimes flicker or go out?

The light bulb in a microwave oven is prone to flickering or burning out due to the high temperatures and vibrations inside the microwave. This is a normal occurrence and the bulb may need to be replaced periodically.

5. Is it safe to change the light bulb in a microwave oven myself?

It is generally not recommended to change the light bulb in a microwave oven yourself. The high voltage and internal components of a microwave can be dangerous if not handled properly. It is best to consult a professional or refer to the manufacturer's instructions for proper replacement procedures.

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