Infrared, visible and ultraviolet radiations/ light have different pro

Infrared, visible and ultraviolet radiations/ light have different properties. Which one of the following statements related to these radiations/light is not correct?

The wavelength of infrared is more than that of ultraviolet radiation.

The wavelength of ultraviolet is smaller than that of visible light.

The photon energy of visible light is more than that of infrared light.

The photon energy of ultraviolet is lesser than that of visible light.

Answer is Right!

Answer is Wrong!

This question was previously asked in

UPSC CDS-2 – 2017

Download PDF Attempt Online

The statement “The photon energy of ultraviolet is lesser than that of visible light” is not correct.

Electromagnetic radiations are ordered by their frequency or wavelength. In order of increasing energy (and frequency, and decreasing wavelength), the spectrum goes from Infrared (IR) to Visible light to Ultraviolet (UV). Photon energy is directly proportional to frequency (E = hf) and inversely proportional to wavelength (E = hc/λ). Therefore, UV radiation has higher frequency, higher photon energy, and shorter wavelength compared to visible light and infrared radiation.

Statement A is correct because IR has a longer wavelength than UV. Statement B is correct because UV has a shorter wavelength than visible light. Statement C is correct because visible light has higher energy than IR. Statement D claims UV energy is lesser than visible light energy, which is false; UV energy is higher than visible light energy.

Join Our Telegram Channel

More similar MCQ questions for Exam preparation:-