Question

To which region of the electromagnetic spectrum do the following wavelengths belong:
a)$250nm$
b)$1500nm$

Answer 1

Hint: Use electromagnetic spectrum to find the range of each radiation and check what wavelength falls into which type of radiation.

Complete step-by-step answer:
a)The range of ultraviolet radiation is from $100nm$ to $400nm$. So $250nm$ falls under ultraviolet radiation.
b)The range of infrared radiation is from $780nm$ to $1mm$. So $1500nm$ falls under infrared radiation.

Additional information:
The electromagnetic spectrum is the range of frequencies (the spectrum) of electromagnetic radiation and their respective wavelengths and photon energies. The electromagnetic spectrum covers electromagnetic waves with frequencies ranging from below one hertz to above ${10^{25}}$ hertz, corresponding to wavelengths from thousands of kilometers down to a fraction of the size of an atomic nucleus. This frequency range is divided into separate bands, and the electromagnetic waves within each frequency band are called by different names; beginning at the low frequency (long wavelength) end of the spectrum these are radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays at the high-frequency (short wavelength) end. The electromagnetic waves in each of these bands have different characteristics, such as how they are produced, how they interact with matter and their practical applications. The limit for long wavelengths is the size of the universe itself, while it is thought that the short wavelength limit is in the vicinity of the Planck length. Gamma rays, X-rays, and high ultraviolet are classified as ionizing radiation as their photons have enough energy to ionize atoms, causing chemical reactions.

Note:
The electromagnetic spectrum is shown in the figure below.
As we can see in the figure, the visible region of light falls in the 400-800nm range.