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Physics · 2023 · 2 marks
CBSE 2023 · Region 2 · Set 1 · Q20
(a) How are infrared waves produced? Why are these waves referred to as heat waves? Give any two uses of infrared waves.
(a)
How are infrared waves produced ? Why are these waves referred to as heat waves? Give any two uses of infrared waves.
OR
(b)
How are X-rays produced ? Give any two uses of these.
Marking-scheme solution
(a)
Infrared waves are produced by hot bodies and vibrations of molecules.
They are referred as heat waves because they are readily absorbed by water molecules and increase their thermal energy and heat them.
Uses
1) Dehydration of fruits.
2) In greenhouse Effect.
3) In remote switches.
OR
(b)
When fast moving electrons strike a heavy target like tungsten, X-rays are produced.
Two uses –
1. Used as a diagnostic tool in medicine,
2. Treatment for certain forms of cancer.
3. To study crystal structure.
All Electromagnetic Waves questions2023 question paperNCERT solutions: Electromagnetic WavesPractice Electromagnetic Waves →
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CBSE Class 12 Physics past-paper question from the 2023 board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.