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JEE Main 2026 Apr 5 Shift 2, Physics Q18: Wave Nature of Matter

JEE Main2026Apr 5, Shift 2Physics
Q.

An electron is travelling with a velocity in free space and when it enters a medium, its velocity is reduced by 20%. The de Broglie wavelength of electron in the medium is , where is its de Broglie wavelength in free space. The value of is _____.

  1. A

    1.20

  2. B

    1.0

  3. C

    1.25

  4. D

    0.75

Solution

De Broglie wavelength is inversely proportional to speed: .

When velocity reduces by 20%, the new speed is . So:

.

.

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