2) Of the following, which has the shortest de Broglie wavelength? A) an airplane moving at a velocity of 300 mph B) a helium nucleus moving at a velocity of 1000 mph C) a nitrogen molecule moving at a velocity of 1000 mph D) a nitrogen molecule moving at a velocity of 5000 mph

B) a helium nucleus moving at a velocity of 1000 mph

Explanation:

According to the De Broglie relation

λ = h/mv

h = planks constant

m = mass of the body

v = velocity of the body.

As we can see from De Broglie's relation, the wavelength of matter waves depends on its mass and velocity. Hence, a very small mass moving at a very high velocity will have the greatest De Broglie wavelength.

Of all the options given, helium is the smallest matter. A velocity of 1000mph is quite high hence it will have the greatest De Broglie wavelength.