Arrange the following in order of ascending order of frequency : (a) W band (b) P band (c) Q band (d) C band The correct order of sequence is
(b), (d), (c) and (a)
The microwave band designations, with the four in question highlighted:
| Band | Frequency |
|---|---|
| P (b) | 0.23–1 GHz |
| L | 1–2 GHz |
| S | 2–4 GHz |
| C (d) | 4–8 GHz |
| X | 8–12 GHz |
| Ku, K, Ka | 12–40 GHz |
| Q (c) | 33–50 GHz |
| W (a) | 75–110 GHz |
Ascending order:
\(P \lt C \lt Q \lt W \Rightarrow (b),\,(d),\,(c),\,(a)\)
How to fix the sequence without a table. The letters were deliberately scrambled as wartime code names, so alphabetical order tells you nothing — but two anchors carry most of the work. P stands for "previous" (the original long-wave radar band) and is the lowest of all; W is the highest of the standard letters, sitting in the millimetre-wave region just below the terahertz gap. That places (b) first and (a) last, which by itself eliminates every option but the first.
What the bands are used for — a useful cross-check, since applications climb with frequency:
P and L: long-range surveillance radar and GPS, where atmospheric attenuation is low. C: weather radar and satellite links. Q and W: millimetre-wave radar, automotive collision-avoidance (77 GHz) and radio astronomy, where the short wavelength gives fine resolution from a small antenna, at the cost of heavy absorption by rain and water vapour.
Hence, the ascending order of frequency is (b), (d), (c), (a).
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