Match List I with List II
| LIST I | LIST II | ||
|---|---|---|---|
| A. | X-rays | I. | \( 1\times10^{16} - 3\times10^{21}\,\mathrm{Hz} \) |
| B. | Microwaves | II. | \( 1\times10^{9} - 3\times10^{11}\,\mathrm{Hz} \) |
| C. | Radiowaves | III. | \( 1\times10^{18} - 5\times10^{22}\,\mathrm{Hz} \) |
| D. | γ-rays | IV. | \( 5\times10^{5} - 10^{9}\,\mathrm{Hz} \) |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → A-I, B-II, C-IV, D-III
In the electromagnetic spectrum the frequency rises in the order radio waves, microwaves, X-rays, γ-rays, so the four frequency ranges can be arranged by their position.
(A) X-rays — this matches (I) \( 1\times10^{16} - 3\times10^{21}\,\mathrm{Hz} \). These are very high frequencies, above the ultraviolet.
(B) Microwaves — this matches (II) \( 1\times10^{9} - 3\times10^{11}\,\mathrm{Hz} \). They lie between the radio waves and the infrared.
(C) Radiowaves — this matches (IV) \( 5\times10^{5} - 10^{9}\,\mathrm{Hz} \). They have the lowest frequencies of the four.
(D) γ-rays — this matches (III) \( 1\times10^{18} - 5\times10^{22}\,\mathrm{Hz} \). They reach the highest frequencies of the spectrum.
NCERT (2026-27):
Radio Waves – “Radio waves are produced by the accelerated motion of charges in conducting wires. … They are generally in the frequency range from 500 kHz to about 1000 MHz.”
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).”
X-rays – “… It covers wavelengths from about 10–8 m (10 nm) down to 10–13 m (10–4 nm).”
Gamma Rays – “They lie in the upper frequency range of the electromagnetic spectrum and have wavelengths of from about 10–10m to less than 10–14m.”