Match List I with List II
| LIST I EM waves | LIST II Production Source | ||
|---|---|---|---|
| A. | Radio waves | I. | radioactive decay of nucleus |
| B. | Infra-red rays | II. | rapid acceleration of electrons in aerials |
| C. | Gamma rays | III. | inner shell electrons move from one energy level to a lower level |
| D. | Ultraviolet rays | IV. | vibration of atoms in hot bodies |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → A-II, B-IV, C-I, D-III
Each region of the electromagnetic spectrum has its own characteristic source, from accelerated charges for the longest waves to the nucleus for the shortest.
(A) Radio waves — this matches (II) rapid acceleration of electrons in aerials. Charges made to oscillate rapidly in an aerial radiate the longest electromagnetic waves.
(B) Infra-red rays — this matches (IV) vibration of atoms in hot bodies. The vibrating atoms and molecules of a hot body emit infrared radiation.
(C) Gamma rays — this matches (I) radioactive decay of nucleus. They come from transitions inside the nucleus, as in radioactive decay, and have the shortest wavelengths.
(D) Ultraviolet rays — this matches (III) inner shell electrons move from one energy level to a lower level. Energy jumps of this size in atoms give ultraviolet radiation.
NCERT (2026-27):
Gamma Rays – “… Table 8.1 summarises different types of electromagnetic waves, their production and detections. As mentioned earlier, the demarcation between different regions is not sharp and there are overlaps.”
| 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- |