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Calculate the wavelength (in nanometre) associated with a proton moving at 1.0 × 10³ m s^−1. Mass of proton = 1.67 × 10^−27 kg and h = 6.63 × 10^−34 Js

1. 0.40 nm
2. 2.5 nm
3. 14.0 nm
4. 0.32 nm

Correct answer: 0.40 nm

Solution

lambda = h/(m*v) = 6.63e-34 / (1.67e-27 * 1.0e3) = 3.97e-10 m = 0.40 nm.

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