要晒所有em wave 係come from天然和人造

simon

2010-01-03 6:45 am

based on my knowledge

天然的有
visible light is from sun as well as ultra violet ,
gama wave from unstable atoms.
infrared from any object with temperature.

人造的
radio wave,
x-ray,
laser.
mircro wave
low frequency wave used for tv

問題,請補充仲有冇其它我冇寫到的or 有冇錯誤？

更新1:

is it that 所有em wave 都可以來自天然和所有em wave 都可以人造的除左gama wave?? 請confirm this questions (最好用中文吧)

更新2:

really last question, in fact, the question i ask is really based on the CURRENT ELETROMAGNETIC SPETRUM(i.e. from the low frequency of Tv wave to the highest frequency of gamma wave).

更新3:

And what i want to ask is that1 are these waves on the spectrum from natrual?2OR a part of some are detected from natural and a part of some from artificial experiment TO form current spectrum?

更新4:

if no evidence of these wave exist, it is impossible to show people the spectrum of the wave from lowest frequencies and highest frequencies which existed.

回答 (1)

天同

2010-01-03 9:04 am

✔ 最佳答案

In fact, you can't list them all.

There is naturally occuring the whole electromagnetic spectrum. From very low frequencies to exremely high frequencies.

Any star, including our sun, emits the spectrum of electromagentic waves because of their temperature (blackbody radiation). High frequency electromagentic waves normally come from explosion of stars, qusars etc. These are termed as "gamma ray burst".

Most of the waves in the electromagnetic spectrum can be produced artificially, except extremely high frequency gamma rays.

2010-01-10 01:20:16 補充：
Human knowledge at present still cannot determine if there is any upperbound of the electromagnetic spectrum (i.e. the highest frequency end). In theory, a "black body" could emit all possible frequencies.

2010-01-10 01:20:34 補充：
Radiation that produced artificially depends on the frequency range which is of use. Some frequency bands within the spectrum is of no practical purpose, and hence there is no point of producing them artificially.

👍 0 👎 0