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Identify the electromagnetic… (Class 12 Physics 2023, Q21)

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PhysicsCBSE Class 12 · Board exam 2023, set 55/5/1 · 2 marks · Very short answer

CBSE Class 12 Physics 2023: question 21

Set in the CBSE Class 12 board exam of 2023, paper 55/5/1, section B, question 21, for 2 marks. Try it first; the hints and our step-by-step solution are below.

Q21 · 2 marks · Very short answerElectromagnetic Waves

Identify the electromagnetic wave whose wavelengths range is from about
(a) m to about m.
(b) m to about m.
Write one use of each.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2023 board paper, set 55/5/1.

Hints

Open one hint at a time and try again before the next.

Hint 1

Recall the order of the electromagnetic spectrum from gamma rays to radio waves.

Hint 2

Wavelengths shorter than UV but longer than about m, and wavelengths of mm to cm size, belong to two well-known bands.

Step-by-step solution

Each step shows the marks it earns, as an examiner would award them. Checked by an independent re-solve from the question paper.

  1. (a) The range m to m corresponds to X-rays.

    ½ mark

  2. One use: X-rays are used as a diagnostic tool in medicine, for example to detect bone fractures. They are also used to study crystal structure.

    ½ mark

  3. (b) The range m to m corresponds to microwaves.

    ½ mark

  4. One use: microwaves are used in radar systems for aircraft navigation. They are also used in microwave ovens.

    ½ mark

Answer: (a) X-rays – medical diagnosis; (b) Microwaves – radar for aircraft navigation

Where the marks are

  • Identifies X-rays (½ mark)
  • One correct use of X-rays (½ mark)
  • Identifies microwaves (½ mark)
  • One correct use of microwaves (½ mark)

Revise the chapter

Practise this chapterBoard-style questions from Electromagnetic Waves, one at a time, marked against the answer key and marking points.Back to the full paper2023 board paper, set 55/5/1: every question, by section.

The question is transcribed from the official paper; figures are described in words. The solution, hints and chapter tag are ours. Spotted an error? Write tosupport@questionbuddy.in.