CBSE 2022 · Region 5 · Set 1 · Q11 · 3 marks
(a)Arrange the following electromagnetic radiation in the ascending order of their frequencies : X-rays, microwaves, gamma rays, radio waves(ii)Write two uses of any two of these radiation.With the help of a ray diagram explain the working of a reflecting telescope. Mention two advantages of a reflecting telescope over a refracting telescope.
(a)
Arrange the following electromagnetic radiation in the ascending order of their frequencies : X-rays, microwaves, gamma rays, radio waves
(ii)
Write two uses of any two of these radiation.
With the help of a ray diagram explain the working of a reflecting telescope. Mention two advantages of a reflecting telescope over a refracting telescope.
Marking-scheme solution
(a)
Radio waves < microwaves < X-rays < gamma rays
(ii)
Two uses each of any two of the radiation
Radio waves-
TV transmission
Radio broadcast
Mobile communication
Radio telescope
Microwaves-
Microwave oven
Speed of automobiles
Radar
Air craft navigation
Gamma rays-
Treatment of cancer
Sterilisation and disinfection
X rays-
Diagnostic tool in medicine
Treatment for certain forms of cancer
Ray diagram of reflecting telescope
(Diagram labels: Secondary mirror, Objective mirror, Eyepiece)
Working: Parallel beam of light gathered by objective mirror is reflected to the secondary mirror, which further forms the image in front of the eyepiece.
Two Advantages
High resolving power
No chromatic aberration
Reduced spherical aberration
Brighter image is formed
Easy mechanical support
Large magnifying power
Electromagnetic WavesElectromagnetic SpectrumUnderstandshort_answereasy
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CBSE Class 12 Physics past-paper question from the 2022board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.