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The wavelength λₑ of an electron and λₚ of a photon of same energy E are related by:

1. λₚ ∝ λₑ
2. λₚ ∝ √λₑ
3. λₚ ∝ 1/√λₑ
4. λₚ ∝ λₑ²

Correct answer: λₚ ∝ 1/√λₑ

Solution

For an electron, de Broglie wavelength λₑ is inversely proportional to the square root of its energy (E), while for a photon, wavelength λₚ is inversely proportional to its energy. Combining these relations gives λₚ ∝ 1/√λₑ.

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