If a particle of mass 5.0 mg moves with the speed of 8.0 m/sec, then the de-Broglle's wavelength will be:
Correct answer: D. 1.66 x 10^-29 m
- A. 1.68 x 10^-27 m
- B. 1.65 x 10^-29 m
- C. 1.70 x 10^-25 m
- D. 1.66 x 10^-29 m
Explanation
Explanation: The de Broglie's wavelength (λ) of a particle is given by the equation: λ = h / pWhere h is the planck's constant and p is the momentum of the particle. The momentum (p) of a particle of mass (m) and velocity (v) is given by: p = mvPutting the values in the above equations, we get: p = (5 × 10-6kg)×(8m/s) = 4 × 10-5 kgms-1 λ = h/p = 6.626 × 10-34Js / 4 × 10-5 kgms-1 λ = 1.6565 × 10-29 m
This question appeared on the UHS MDCAT 2009 paper, which you can sit online with every answer explained.
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