The infrared region of the electromagnetic spectrum lies between

The correct answer is Option (2) → microwaves and the visible region

In order of increasing wavelength the electromagnetic spectrum runs through gamma rays, X-rays, ultraviolet, visible, infrared, microwaves and radio waves.

Option (1) radio waves and microwaves — Incorrect. Microwaves are short-wavelength radio waves, so these two bands are neighbours. Infrared lies on the shorter-wavelength side of the microwaves.

Option (2) microwaves and the visible region — Correct. The infrared band lies next to the long-wavelength (red) end of the visible spectrum. Beyond it, at still longer wavelengths, come the microwaves.

Option (3) the visible region and the UV region — Incorrect. Ultraviolet lies next to the short-wavelength (violet) end of the visible region. Infrared is on the other side of the visible band.

Option (4) the ultraviolet region and X-rays — Incorrect. These are neighbouring bands of much shorter wavelength than visible light, while infrared waves are longer than visible light.

NCERT (2026-27):
Infrared Waves – “Infrared waves are produced by hot bodies and molecules. This band lies adjacent to the low-frequency or long-wave length end of the visible spectrum.”

Summary – “… Different regions are known by different names; γ-rays, X-rays, ultraviolet rays, visible rays, infrared rays, microwaves and radio waves in order of increasing wavelength from 10^–2 Å or 10^–12 m to 10⁶ m.”