Final answer:
The velocity of the helium atom is approximately 1.46 x 10^3 m/s.
Step-by-step explanation:
The de Broglie wavelength (λ) of an object is given by the equation λ = h/mv, where h is Planck's constant (6.626 x 10^-34 Js), m is the mass of the object, and v is its velocity. To find the velocity (v) of the helium atom, we can rearrange the equation to v = h/(mλ). Plugging in the values, we have:
v = (6.626 x 10^-34 Js) / (2 x 6.646 x 10^-27 kg x 4.30 x 10^-12 m).
Simplifying the expression gives v ≈ 1.46 x 10^3 m/s.