Planck's constant is 6.6 * 10^-34 J·s and the proton mass is 1.7 * 10^-27 kg.The speed of a proton whose de Broglie wavelength is 4.0 * 10⁷ m is A)7.8 * 10^-20 m/s. B)9.9 * 10² m/s. C)1.9 * 10⁶ m/s. D)3.9 * 10⁶ m/s.

Question

Quizplus · Accepted Answer

The de Broglie wavelength λ of a particle is given by: 
λ = h/mv 
where h is Planck's constant, m is the mass of the particle, and v is its velocity.

Rearranging the above equation, we get: 
v = h/(mλ)

Substituting the given values, we get: 
v = (6.6 x 10^-34 J·s) / [(1.7 x 10^-27 kg) x (4.0 x 10^-10 m)] 
v ≈ 1.9 x 10^6 m/s

Therefore, the correct answer is C) 1.9 x 10^6 m/s, which is approximately 1.9 x 10^16 m.

Planck's Constant Is 6