Microwave ovens vs. cordless phones

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In summary, the reason why a microwave oven can heat your food but a 2.4 GHz cordless phone does not heat your body is due to the difference in power being used. Microwave ovens use up to 1000 W while cordless phones and cell phones use powers on the order of 100 mW. As for the effect of 2.4 GHz waves on water molecules, it depends on the amount of power being used and the insulation of the water. The various regulatory agencies limit the amount of RF energy that can be deposited by a device, and manufacturers reduce this by using low-power transmitters and positioning the antenna away from the head.
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overlook1977
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If a microwave oven is using the same frequency as a 2.4 GHz cordless phone, why is it that a cordless phone does not heat your body when you use it? I am assuming it has something to do with concentration or focus of the waves? I would assume a cordless phone or anything that emits waves in this frequency would have to have some measurable effect on water molecules in its proximity, am I correct?
 
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  • #2
It's simply the amount of power being used. Microwave ovens use up to 1000 W, while cordless phones and cell phones use powers on the order of 100 mW.
 
  • #3
do you know if a cordless phone or other 2.4 GHz wireless device can make a measurable difference in nearby water temperature (however small)?
 
  • #4
Depends how good your measurement is (and how well insulated the water is) !

1mW into a glass (100cc) of water, would heat it by 8.5mK in 1 hour assuming no heat was lost.
 
  • #5
Makes sense...I was forgetting about wave intensity. Thanks!
 
  • #6
The various regulatory agencies limit the amount of RF energy that is allowed to be deposited by a device. The limit of interest is called SAR (specific absorption rate) and is in units of W/kg. I don't know what the limit is for cordless phones, but manufacturers generally do two things to reduce it. First, they use low-power transmitters. Second, they position the antenna as far away from the head as they reasonably can.
 

1. How do microwave ovens interfere with cordless phones?

Microwave ovens emit electromagnetic waves, which can cause interference with cordless phones that operate on the same frequency. This can result in poor call quality or even dropped calls.

2. Can using a microwave oven while using a cordless phone be dangerous?

There is no evidence to suggest that using a microwave oven and a cordless phone at the same time is dangerous. However, it is important to maintain a safe distance from the microwave while it is in use and to use the cordless phone away from the oven to avoid interference.

3. How can I reduce interference between my microwave and cordless phone?

To reduce interference, make sure the microwave and cordless phone are placed at least 10 feet apart. Additionally, you can try changing the channel on your cordless phone to a different frequency or using a cordless phone with a higher frequency, such as 5.8 GHz.

4. Is it safe to use a cordless phone inside a microwave oven?

No, it is not safe to use any electronic device, including a cordless phone, inside a microwave oven. Microwaves are designed to contain and direct electromagnetic waves, and using other devices inside the oven can cause damage to both the device and the oven.

5. Can a cordless phone interfere with a microwave oven's operation?

No, a cordless phone cannot interfere with a microwave oven's operation. Microwaves are designed to operate at a much higher frequency than cordless phones, so they should not be affected by the signals from the phone.

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