When atoms jiggle, their charged constituens get accelerated, and accelerated charges radiate electromagnetically (keep in mind that like most of physics, this is a lie-to-children).
The (idealized) distribution of electromagnetic radiation is given by Planck's law, which cannot be derived from the classical picture I gave above because of the so-called ultraviolet catastrophe - you need quantum mechanics for that.
The infrared part of the spectrum has no special association with heat energy - it's just that radiation intensity will peak there at 'moderate' temperatures and in particular room temperature. For example, the sun has an effective temperature of ~5800°C and peaks in the visible spectrum, whereas the cosmic microwave background corresponds to thermal radiation at ~2.7 K.
As to your other question - it is indeed possible to transfer heat via thermal radiation as the emission processes come with associated absorption processes. The other modes of heat transfer are convection (ie moving heated matter around) and conduction (ie the atoms transfer their jiggling by collisions).
Wrong:
"since infrared waves have a shorter wavelength"
Infrared has longer wavelength than visible and visible longer wavelength than ultraviolet .
White is a term for visible light mixed wavelengths. In the plot you can see that almost half of the sun's radiated energy arrives as visible light. The white buildings reflect this visible light which otherwise,impinging on the surfaces would be absorbed and turned into infrared by the interactions, adding to the arriving infrared.
What is absorbed and what is reflected depends on the chemical bonds of the surfaces, whether the incoming radiation can excite molecular states of the materials. Infrared is in frequencies/wavelengths of the black body radiation of bodies in the temperature ranges comfortable for the human body, so they easily raise the vibrational and rotational levels of solids and liquids and the kinetic energy of gasses.
37C curve seen here practically all in infrared, and lower temperatures more so.
Thus white paint will not reflect infrared as efficiently as visible, a large part of infrared will be absorbed as also some part of visible will scatter at the surface and degrade to infrared. Infrared can be reflected by metal mirrors, from the collective fields in metals . If you put aluminum foil in front of a heater you are sheltered from most of the heat which is reflected, but some of it is absorbed as can be seen by touching the foil.
If I expose an object to EM radiation only from the infrared spectrum, will it only reflect back infrared?
Yes, but most of it will be absorbed ( except by mirror metal surfaces) because the materials have the receptors for these wavelengths. This is due to the fact that larger wavelengths have photons with less energy which cannot excite higher energy levels.The energy of the photons goes as h*c/lamda where h is plancks constant, lamda the wavelength and c the velocity of light.
Is this true for other types of EM radiation?
No.Visible and ultraviolet by scatterings degrade their energy down to infrared frequencies, depending on the material.
Is it possible to make an object that looks white and absorbs a lot of infrared radiation?
Usually most of the infrared will be absorbed except by mirror metal surfaces.
If an object reflects most of the EM radiation that it receives of a particular wavelength λ, will it also reflect most of the radiation it receives of wavelengths less than λ (and absorb most of the radiation of wavelengths larger than λ)? Is this why objects that reflect most visible light (and hence look white) also reflect most infrared radiation (since infrared waves have a shorter wavelength)?
There is no such rule. It depends on the material and its chemical bonds.
Best Answer
For a black car all of the visible light energy turns to heat otherwise you would not be seeing it black.
A reflective car would be a better bet, as long as it also reflects in the uv and infrared.
I live in Greece and used to have a white car. I now have a silvery car, but it gets equally hot as the white one used to, in the sun.