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The ground state energy of… (Class 12 Physics 2023, Q23)

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

CBSE Class 12 Physics 2023: question 23

Set in the CBSE Class 12 board exam of 2023, paper 55/1/1, section B, question 23, for 2 marks. Try it first; the hints and our step-by-step solution are below.

Q23 · 2 marks · Very short answerAtoms

The ground state energy of hydrogen atom is eV. What is the potential energy and kinetic energy of an electron in the third excited state ?

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

Hints

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

Hint 1

Ground state is , so the third excited state is .

Hint 2

In Bohr's model, and .

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. Total energy eV; third excited state means .

    ½ mark

  2. eV

    ½ mark

  3. Potential energy eV

    ½ mark

  4. Kinetic energy eV

    ½ mark

Answer: PE = eV, KE = eV

Where the marks are

  • Identifies and uses (½ mark)
  • eV (½ mark)
  • PE eV (½ mark)
  • KE eV (½ mark)

Revise the chapter

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