Which of the following electromagnetic radiations has the maximum energy?

The answer is D, X-rays. Photon energy is given by E = hf, and frequency rises as wavelength falls. Among the four options, X-rays have the shortest wavelengths (roughly 0.01 to 10 nm), so they carry the most energy per photon.

• Visible light (A): wavelength about 400 to 700 nm. It is far less energetic than X-rays.
• Infrared (B): wavelength above about 700 nm. It is felt as heat, but each photon carries comparatively little energy.
• Ultraviolet (C): wavelength about 10 to 400 nm. It is more energetic than visible light, but X-rays lie beyond it on the spectrum.

The core concept is the ordering of the electromagnetic spectrum by energy: radio, microwave, infrared, visible, ultraviolet, X-ray, gamma. Gamma rays would beat X-rays, but gamma is not an option here. This ordering links to Mains GS-III (science and technology) through ionising radiation, medical imaging, and why UV-B affects the ozone layer and human health.

Trap: Aspirants pick UV because it sits just beyond visible light. Energy depends on frequency, not on how close a band is to visible light, so always compare wavelengths.