Question

Hot objects with temperatures of 10 million Kelvin give off most of their radiation in which part of the electromagnetic spectrum?

Answer 1

Well, this can be estimated with Wien's Displacement Law:

`lambda_(max) = (2.8977729 xx 10^(-3) "m"cdot"K")/T`,

assuming your hot object of interest is a blackbody (not at all related to a woman!), i.e. an opaque body that does not reflect any light.

`lambda_(max)` gives the peak wavelength of a blackbody's radiation curve as a function of surface temperature.

So, if we assume the surface temperature of the object is `10^7` `"K"`, then its maximum wavelength is approximately:

`color(blue)(lambda_(max)) ~~ (2.8977729 xx 10^(-3) "m"cdot"K")/(10^7 "K")`

`= 2.90 xx 10^(-10) "m"`

`=` `color(blue)("0.290 nm")`,

which is around the X-ray region, with wavelength range `0.01 - "10 nm"`.