What is the de Broglie wavelength of a dust particle that has a mass of 1e-10 kg and a velocity of 0.05m/s?

From the question asked, we need to identify the key bits of information.

Firstly, we are asked to find the de Broglie wavelength, so we write down the de Broglie relation:

lambda = h/p

In this equation we want to find the wavelength lambda, and we know h is Planck's constant, h = 6.63e-34 Js. So the remaining term we need to determine is p, the momentum.

In order to find the momentum, we use the relation p=m*v, using the mass and velocity given in the question.

We can now calculate the wavelength by plugging p into the de Broglie formula.

lambda = 1.33e-22 m