Match List-I with List-II
| List-I | List-II | ||
| Electromagnetic Waves | Use | ||
| (A) | Ultraviolet rays | (I) | Diagnostic tool in medicine |
| (B) | Infrared radiations | (II) | Radar system |
| (C) | Microwaves | (III) | Physical therapy |
| (D) | X - rays | (IV) | kill germs in water |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → (A) - (IV), (B) - (III), (C) - (II), (D) - (I)
Each use depends on how the radiation interacts with matter, which is set by its wavelength.
(A) Ultraviolet rays — this matches (IV) kill germs in water. UV photons are energetic enough to damage the DNA of bacteria, so UV lamps sterilise water.
(B) Infrared radiations — this matches (III) Physical therapy. Infrared is absorbed as heat by the skin and muscles, which is why infrared lamps are used in physiotherapy.
(C) Microwaves — this matches (II) Radar system. Their short wavelength (a few cm) lets them travel as a narrow beam and reflect well from aircraft, so they are used in radar.
(D) X - rays — this matches (I) Diagnostic tool in medicine. X-rays pass through soft tissue but are absorbed by bone, giving the familiar X-ray images.
NCERT (2026-27):
Ultraviolet Rays – “… UV lamps are used to kill germs in water purifiers.”
Infrared Waves – “… Infrared lamps are used in physical therapy.”
Microwaves – “Microwaves (short-wavelength radio waves), with frequencies in the gigahertz (GHz) range, are produced by special vacuum tubes (called klystrons, magnetrons and Gunn diodes). Due to their short wavelengths, they are suitable for the radar systems used in aircraft navigation.”
X-Rays – “… X-rays are used as a diagnostic tool in medicine and as a treatment for certain forms of cancer.”