If the momentum of a particle is doubled, then its de-Broglie wavelength will:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → become half
The de Broglie wavelength of a particle is \( \lambda = h/p \), so it is inversely proportional to the momentum.
\( \displaystyle \lambda' = \frac{h}{2p} = \frac{\lambda}{2} \)
Doubling the momentum halves the wavelength.
NCERT (2026-27):
Summary – “… 9. The de Broglie wavelength (\( \lambda \)) associated with a moving particle is related to its momentum p as: \( \lambda = h/p \).”