Question

IR region lie between:
A. Radio waves and microwave regions
B. Microwave and visible
C. Visible and UV
D. UV rays and x-ray region

Answer 1

Hint: IR stands for infrared. The IR region or infrared region refers to the range in the electromagnetic spectrum where the radiations are of an infrared nature. The infrared range has a frequency higher than microwaves and lower than the visible range. In terms of wavelength, it has wavelengths greater than the visible range but lesser than the microwave range.

Complete step-by-step answer:
The IR region stands for the range of the electromagnetic spectrum where the electromagnetic radiations are termed to be of infrared radiation nature. IR stands for infrared. Infrared radiation has a wavelength that is lesser than microwaves and greater than the visible region. Alternatively, it can be said that the frequency of infrared radiation is lesser than the visible region and greater than the microwave region, since wavelength and frequency of an electromagnetic wave are inversely proportional to each other.
The wavelength of an infrared wave is about ${{10}^{-5}}m$ while its frequency is of the order of ${{10}^{13}}Hz$.
Hence, the infrared region lies between the microwave and visible region.
Therefore, the correct option is B) Microwave and visible.

Note: Knowing the order of the radiations in the electromagnetic spectrum is key in solving such types of questions. The sequence can be memorized with the help of clever mnemonics. One such mnemonic is-
“ R aging M artians I nvaded V enus U sing X -ray G uns”
Where the underlined letters stand for Radio waves, Microwaves, Infrared region, Visible region, Ultraviolet region, X-ray region, Gamma ray region, which is the order of the electromagnetic spectrum in the ascending order of increasing frequency of radiation.