Match List I with List II
LIST I | LIST II | ||
A. | Radiowaves | I. | Point contact diodes |
B. | Microwaves | II. | Ionization chamber |
C. | Infrared rays | III. | Receivers aerial |
D. | X-rays | IV. | Bolometer |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → A-III, B-I, C-IV, D-II
Each region of the electromagnetic spectrum is produced and detected by a characteristic device; the match follows how each wave is detected.
(A) Radiowaves — this matches (III) Receivers aerial. Radio waves are picked up by the aerial of a receiver.
(B) Microwaves — this matches (I) Point contact diodes. Microwaves are detected by point contact diodes.
(C) Infrared rays — this matches (IV) Bolometer. Infrared radiation is detected by its heating effect, using thermopiles and bolometers.
(D) X-rays — this matches (II) Ionization chamber. X-rays ionise a gas, so they are detected by Geiger tubes and ionisation chambers.
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 |
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 |
Ultraviolet | 400 nm to 1nm | Inner shell electrons in atoms moving from one energy level to a lower level | Photocells |
X-rays | 1nm to 10−3 nm | X-ray tubes or inner shell electrons | Photographic film |
Gamma rays | <10−3 nm | Radioactive decay of the nucleus | -do- |