Question

What's the wavelength in meters of an electron traveling at 9.5 x 10^7 m/s? The mass of an electron is 9.11 x 10^-28 g.

Select one:
a. 7.66 x 10-15 m
b.7.66 x 10-12 m
c. 3.47 x 1027 m
d. 3.47 x 1030 m

Answer 1

where:

• A is the wavelength in m.

• h = 6.626 x 10-34Js is Planck's

constant.

• m is the mass of the particle, such as the electron, in kg. The particle must have a mass for this relation to work.

• v is the forward velocity of the particle, in m/s.

Hence, the wavelength is:

6.626 x 10-34J.s

(9.1094 × 10 −³¹kg) (5 × 10³m/s)

We know that 1 J 1 kg. m²/s². So:

6.626 × 10-³4 g · m² / ø

9.1094 x 10 - 31) (5 x 105 m/s)

= 1.455 x 10-9 m

=

= 1.455 nm