Match List – I with List – II.
| LIST I | LIST II | ||
|---|---|---|---|
| (A) | Radio waves | (I) | 1 mm to 700 nm |
| (B) | Infrared waves | (II) | 700 nm to 400 nm |
| (C) | Light waves | (III) | 1 nm to \( 10^{-3} \) nm |
| (D) | X-rays | (IV) | > 0.1 m |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → (A)-(IV), (B)-(I), (C)-(II), (D)-(III)
The electromagnetic spectrum is arranged by wavelength, from the longest (radio waves) to the shortest (gamma rays).
(A) Radio waves — this matches (IV) > 0.1 m. They have the longest wavelengths of the four.
(B) Infrared waves — this matches (I) 1 mm to 700 nm. They lie just beyond the red end of the visible light.
(C) Light waves — this matches (II) 700 nm to 400 nm. This is the visible range, from red (700 nm) to violet (400 nm).
(D) X-rays — this matches (III) 1 nm to \( 10^{-3} \) nm. They have very short wavelengths, shorter than ultraviolet.
NCERT (2026-27):
Gamma Rays – “… Table 8.1 summarises different types of electromagnetic waves, their production and detections.”
| Type | Wavelength range | Production | Detection |
|---|---|---|---|
| Radio | > 0.1 m | Rapid acceleration and decelerations of electrons in aerials | Receiver’s aerials |
| Microwave | 0.1m to 1 mm | Klystron valve or magnetron valve | Point contact diodes |
| Infra-red | 1mm to 700 nm | Vibration of atoms and molecules | Thermopiles Bolometer, Infrared photographic film |
| Light | 700 nm to 400 nm | Electrons in atoms emit light when they move from one energy level to a lower energy level | The eye Photocells Photographic film |
| Ultraviolet | 400 nm to 1nm | Inner shell electrons in atoms moving from one energy level to a lower level | Photocells Photographic film |
| X-rays | 1nm to 10-3 nm | X-ray tubes or inner shell electrons | Photographic film Geiger tubes Ionisation chamber |
| Gamma rays | <10-3 nm | Radioactive decay of the nucleus | -do- |