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## Homework Statement

A) The wavelenght of an electron in an electron microscope is 0.0122nm.What is the electron velocity?

B) Sodium lights emit light of yellow colour, with photons of wavelength 580nm. What is the energy of these photons?

## Homework Equations

v=w/k

k=2pi/wavelenght

w=2pi*f

## The Attempt at a Solution

A) k=2pi/0.0122nm = 5.15x10^+11

w=2pi(c/wavelenght) = (2pi*3E8)/0.0122nm

w=1.545E19

v=w/k=3E8 m/s

B)E=hf = hc/lambda

e=(4.136E-15)(3E8)/589E-9

e=2.107eV

The answer to A should be 5.95E7 m/s and the answer to B should be 4.3E-7eV. Am i right in my answers or are the teachers answers wrong?