What is the wavelength, in meters, of an alpha particle with a kinetic energy of 8.0*10^-13 J. [mass of an alpha particle = 4.00150 amu; 1 amu = 1.67*10^–27 kg]?

1 Answer
Jun 21, 2018

#6.4 × 10^-15\ "m"#

Explanation:

de-Broglie wavelength is given by

#λ = h/p#

Relation between #p# and #"K"# is

#p = sqrt("2Km")#

So, the wavelength now becomes

#λ = h/sqrt("2mK")#

Where

  • #λ =# Wavelength of particle
  • #h =# Planck’s constant
  • #p =# Momentum of particle
  • #"m ="# Mass of particle
  • #"K ="# Kinetic energy of particle

#λ = (6.626 × 10^-34\ "J s")/sqrt(2 × 4.00150 cancel"amu" × 1.67 × 10^-27\ "kg"/cancel"amu" × 8.0 × 10^-13\ "J")#

#color(white)(λ) = 6.4 × 10^-15\ "m"#

#color(white)(λ) = 6.4\ "fm"#