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  9. Q68

UKPSC PCS 2024 · Question 68 of 142

What will be the de Broglie wavelength of a ball of mass 0.12 kg moving with a speed of 20 ms–1 ?

Science & Tech

  1. A6.63 × 10–30 m
  2. B6.63 × 10–34 m
  3. C2.76 × 10–30 m
  4. D2.76 × 10–34 mCorrect

Answer: D. 2.76 × 10–34 m

Explanation

de Broglie wavelength = h/mv = 6.63e-34/(0.12 x 20) = 2.76 x 10^-34 m.

Source: UKPSC Combined Upper PCS Prelims GS Paper-I, Series-A, held 14 Jul 2024 (teachingninja PDF); answer from official UKPSC Series-A key

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