Match List-I with List-II
| List-I | List-II |
| Electromagnetic Waves | Application/Importance |
| (A) Ultraviolet rays | (I) As a treatment for certain forms of cancer |
| (B) Microwaves | (II) Maintaining average temperature of the Earth |
| (C) X-rays | (III) Radar system |
| (D) Infrared waves | (IV) To kill germs in water purifier |
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) - (I), (D) - (II)
Each part of the electromagnetic spectrum is used according to how its radiation interacts with matter.
(A) Ultraviolet rays — this matches (IV) To kill germs in water purifier. UV radiation is absorbed by and damages the genetic material of bacteria, so UV lamps kill germs in water purifiers.
(B) Microwaves — this matches (III) Radar system. Their short wavelengths make microwaves suitable for radar used in aircraft navigation.
(C) X-rays — this matches (I) As a treatment for certain forms of cancer. Besides their use in diagnosis, high-energy X-rays destroy cancer cells in radiotherapy.
(D) Infrared waves — this matches (II) Maintaining average temperature of the Earth. The Earth radiates infrared, and part of it is trapped by greenhouse gases (the greenhouse effect), which keeps the Earth warm.
NCERT (2026-27):
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.”
Infrared Waves – “… Infrared radiation also plays an important role in maintaining the earth’s warmth or average temperature through the greenhouse effect.”
Ultraviolet Rays – “… UV lamps are used to kill germs in water purifiers.”
X-Rays – “… X-rays are used as a diagnostic tool in medicine and as a treatment for certain forms of cancer.”