What would the speed of each particle be if it had the same wavelength as a photon of violet light ( λ = 400.0 nm ) ?

a. proton ( mass = 1.673 × 10 − 24 g ) speed: m / s
b. neutron ( mass = 1.675 × 10 − 24 g ) speed: m / s
c. electron ( mass = 9.109 × 10 − 28 g ) speed: m / s
d. alpha particle ( mass = 6.645 × 10 − 24 g ) speed:

To develop this problem we will use the DeBroglie relationship for which the wavelength is considered as

Where,

h = Planck's constant

m = mass

v = Velocity

= Wavelength

Rearranging the equation we have that the speed would be

Our given values are considered

The value of the mass varies, therefore its speed would be given as:

Proton

Neutron  

Electron

Alpha particle

kepler used the data from tycho blahe (his mentor) to construct the laws of planetary motion.