Microwave Definition and 349 Threads

Homework Statement Microwave oven I. The glass window isn't important to the microwave oven's operation, but the metal grid associated with that window certainly is. The grid forms the sixth side of the metal box that traps the microwaves so they cook food effectively. What is the approximate...

How does one convert measurements in radio astronomical terms to temperature (Kelvin)? Specifically: Penzias & Wilson's measurement of CMB was "excess temperature at 4080 Mc/s." HOW does this yield a "value of about 3.5 degrees Kelvin higher than expected?" Basically, how do you get from...

What does string theory have to say about this and how has string theory changed cosmology in terms of verifiable observational predictions?

Can anyone explain how the cosmic microwave background radiation (CMBR) "cooled"...I'm supposing that about 300,000 years or so after the bang, when the universe became transparent, things were hotter than 2.7 degrees above absolute zero we observe today... Wikipedia says: So an expanding...

If one had a microwave oven transformer (MOT) from a microwave that was said to be 1200W, and the transformer itself had an output of 2300V, would that mean that the current would be: Power = Current * Voltage 1200W = Current * 2300V Current = 0.52A The reason I ask is because: I'm...

I have four dual technology (alarm type microwave & pir) sensors, which I would like to wire up as motion sensors that operate a light or buzzer only during the period of detection. The sensors are Rokonet brand, model RK815DT, which display three frontal leds: m/wave, pir, alarm trigger. They...

hi, I'm new to this forum and i would like to pose a question that have been bothering me for awhile. the peak wavelength of the Cosmic Microwave Background (CMB) is lambda_max=[2.898x10^-3 m K]/[2.725 K]=1.06 mm [or 282 GHz], where lambda_max is the maximum, or peak, wavelength, i.e., the...

I am trying to wrap my head around the Cosmic Microwave Background and how it is that the low frequency ancient photons we observe could be only 'passing' us in space now. If we think of a photon as an entity that is traveling away from the origin of the Big Bang at 300,000km/s, why would these...

just wondering if i put oil in a microwave oven will the oil get heated and why? i know polar substances will be heated but I am not sure if the same thing will happen to non-polar substance like oil

I put my tea in the microwave this morning then went to sit on the sofa. I heard some crackling noises, similar to the sound that metal makes when in a microwave. I ran over, and hit stop then opened the microwave. The microwave tray was over to one side. I took the mug off but the tray...

-If you have a magnetron produce __# of microwaves, each with frequency of __ MHz, how can one calculate the power of those microwaves (in watts)? -the microwaves have electric field and magnetic field associated with them, taking just one microwave (in the waveguide) and its associated...

Homework Statement A microwave transmitter (T) and receiver (R) are set up side by side as shown. https://chip.physics.purdue.edu/protected/Giambattista2EMimg/F25-5a.gif" Two flat metal plates (M) that are good reflectors for microwaves face the transmitter and receiver, several meters away...

Hello, This is my first post, so please forgive me if this has been covered before. In my searches I was unable to find any previous threads specifically about this question. I made a statement in a link sharing forum that was immediately disputed. I'm not interested in winning an argument so...

Can standing in front of a microwave actually cause you harm?

Homework Statement peak power consumed by microwave is 1180 W when operated at 120 Vrms. What rms current does that microwave draw? Homework Equations I'm not getting the correct answer, I think I am getting I and V confused with Irms and Vrms and Imax. The Attempt at a Solution...

Dear Friends A fleet of spaceships is given, each equipped with a differential microwave radiometer, just like COBE was, whose detectors are antipodeanly pointing (this way one should catch blue shifted radiation and the other one red shifted). Could their acquisitions be used to...

I was looking at a map of the cosmic microwave background, and began wondering if the cmb would look the same from another vantage point, perhaps Pluto, or a nearby star. Or what about if it were seen from another galaxy? And, in a related question, does the cmb evolve with time? I suppose...

I was curious about microwave ovens and how they work and in particular about the microwave radiation they emit and the halflife of this radiation. My layman's understanding is that microwave ovens use a 2.43GHZ emf to heat up water inside food items by attenuating 1 or more? of the few...

Whenever I cook something in my microwave, sometimes there will be a bug in it and it won't be affected by the microwave. It'll just walk around inside the microwave while the food is cooking. How is it able to do that without getting cooked itself? Thanks.

My daughter claims that when she runs our microwave oven, it disables her laptop computer connection to our wireless router. What might cause that? Will we be sterlizied?? (just joking...I think!) One possibility is that when the microwave oven draws power sparking from a loose 120 wall plug...

Homework Statement A microwave detector is located 0.5m above the surface of a large lake far from the shore. As a star, emitting monochromatic microwave radiation of 21cm wavelength, rises slowly above the horizon, the detector indicates successive maxima and minima in the signal...

Homework Statement A microwave detector is located 0.5m above the surface of a large lake far from the shore. As a star, emitting monochromatic microwave radiation of 21cm wavelength, rises slowly above the horizon, the detector indicates successive maxima and minima in the signal intensity...

Ok, here's the deal. I'm supposed to get mulled wine for tonight... except we don't have a stove or anything, just a microwave. It's been suggested to me that there's such a thing as "microwavable mulled wine" but I'm not sure. So two part question 1.) Does microwavable mulled wine exist...

Homework Statement Hey guys, I have a homework problem in my electromagnetism class that's got me a little stumped. I'm supposed to measure the interior dimensions of my microwave oven and use that to calculate the 5 lowest frequencies at which I can sustain a mode in which I have standing...

Hi, at my Uni we have a lab course where we first take some measurements and then write a report about the experiment. Our current experiment was about microwave diffraction. First, we measured the wave length of the microwaves, and then proceeded to measure the intensity of the scattered...

This is a question I came across in lab. I inserted a reflecter between a microwave transmitter and receptor, with the plane of the reflector parallel the the axis of the beam. The reflector is then moved away. See the setup and data plot in the attachment. I understand that the waves...

Hello all, I was recently assigned a problem in my modern physics class regarding finding the mean energy of Cosmic Microwave Background (CMB) photons. The problem reads as follows: The universe is permeated with primordial microwave radiation that has a mean wavelength of about 2.5 mm...

Hello, I've been watching some videos on youtube of people putting a lit flame into a microwave oven. After a few seconds the flame bursts into a bright ball of plasma, why is this? Is there anywhere online that I can research the science that causes this...

Why isn't our Local Group's dipole for Microwave Background Radiation pointed towards the center of mass for our Local Supercluster? Clusters are suppose to be just infalling towards gravitational well of it's supercluster. http://en.wikipedia.org/wiki/Cosmic_microwave_background" See...

hi , I am confused with these two terms microwave cavity and microwave chamber . Some say that the microwave chamber inside which food gets cooked acts like a resonant cavity ( which I believe is not true ) because resonance must best be avoided inside the chamber .Resonance I think...

We know that the CMB has been decreasing in temperature since the big bang. This is due to the continuing expansion of the universe that results to an increase in the wavelengths of the CMB photons. Increased wavelength => less energy => less temperature. My question is why do the photons have...

With 90% of the observable matter in the universe being Hydrogen (H2), why is it that the microwave background is attributed to the big band and not the emission of microwaves from excited state hydrogen?

Ok, so as I understand it microwave radiation can be detected from 'outer space' but what does that prove? I really don't see why it should be evidence of a big bang, absolutely none whatsoever, infact microwaves would probably one of the last things on my list as evidence. What is the...

Why a cellphone rings inside microwave oven? Does the microwave oven don't block cellphone radiation?

Anyone know some decent free software for simulating microwaves in full detail? Ideally I'd like to input autocad drawings to it, of metallic structures, and see the power distribution in 3D.

When you put a metal (conducting) spoon inside a microwave, it takes a few seconds, and then you get sparks, that might damage the microwave. I heard (and cowardly hadn't tested) that putting a spoon inside a cup of water would allow a long 5 minute heating, no sparks and no damage. The riddle...

What's the shape of a microwave beam in a microwave oven? I wonder wether is a ray a small cone, a big cone a band... Does this beam reflects on the inner walls of the microwave or get absorbed? I would say the second one because one side of the food, if it doesn't turn inside the microwave...

I have been trying to find a free (or cheap) software package that can be used to simulate microwave systems (i.e. NOT an EM simulation package) but so far I haven't had much luck. Essentially I would like to be able to "build" systems with mixers, circulators, amplifiers, waveguides etc and...

At a time when pc's come with microprocessors clocked at frequencies of the order of 4 GHz, it must be possible to drive a D/A converter at microwave frequencies. Anyone know of hardware to do this? Anyone know of suitable hardware to transmit the waveform at a power density comparable...

i have a micorwave bench that operates in the X band.I want to know if i can convert it to a microwave spectrometer, with little modification,i have a gunn power supply, at the source end of the bench and a dielectric sample holder at the otherend. if i replace the termination next to the...

How can sub-wavelength (about 12 cm./2.45GHz) radiation escape a microwave oven door slit-under 1 cm. wide. Why not a Faraday cage?

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...

Recently I watched some paper about new propulsion technologies focused in Light e.g Laser and Microwave, so I'd like to know where can I obtain deep information about the subjet, due, papers found it at the internet just describe bit information. I'm interesting mainly in microwave propulsion...

I'm not sure where to put this, Its exactly what the title says: this one shows the grape more clearly, starts properly about 1 minute in, and also quite long sustained plasma with a match, Plasma from a grape! any ideas how? or is it fake? also if you watch any of the other similar...

I quickly read the followoing IEEE paper: http://www.atomicprecision.com/blog/wp-filez/Thim%20-%20Absence%20of%20the%20relativistic%20Doppler%20effect%20...%20.pdf The author claims he proved that he invalidated experimentally the SR prediction of a transverse Doppler effect for...

According to the standard cosmological model, the description for cosmic temperature falls is:T=A*t^-0.5. So when t-->infinite, T-->0. It means the temperature of microwave background will approach 0k after billions of years. Microwave background will disappear?:confused:

Has anyone out there actually tried the kitchen experiment of placing a continuous line of meltable food (i.e. marshmellows/chocholate/cheese etc.) across the bottom of a microwave oven in hopes of finding the antinodes of a standing wave by looking for regions that melt while the rest of the...

Would plates that are not marked "microwave safe" explode in a microwave oven or crack slowly?

I'm taking a microwave devices course this semester, basically it's about wave guides, cavity resonators and such, the problem I'm facing is that I spend a lot of time trying to understand each and every little bit of detail in the course which of-course requires an extensive use of E&M, so I...

Has anyone heard of this proposed test of string theory's extra dimensions? What do you think? Within the realm of reason? Doable within the next decade? Robert === http://www.news.wisc.edu/13422.html ...physicists at the University of Wisconsin-Madison have devised an approach...