wavelength .989 nm strikes a surface the emitted electron has a kinetic energy of .969eu
and you want to know what?
To find the energy of an electron after it is emitted from a surface due to the absorption of photons with a given wavelength, you can use the equation:
E = hc/λ - φ
Where:
E is the kinetic energy of the electron (in joules)
h is the Planck's constant (6.62607015 × 10^-34 J·s)
c is the speed of light (2.998 × 10^8 m/s)
λ is the wavelength of the incident light (in meters)
φ is the work function of the surface material (in joules)
Given:
λ = 0.989 nm = 0.989 × 10^-9 m
E = 0.969 eV
First, convert the kinetic energy from electron volts (eV) to joules by using the conversion factor: 1 eV = 1.602 × 10^-19 J
Kinetic energy in joules (EJ) = 0.969 eV × 1.602 × 10^-19 J/eV
Now, you can solve for the work function (φ):
φ = hc/λ - EJ
Substitute the known values:
h = 6.62607015 × 10^-34 J·s
c = 2.998 × 10^8 m/s
λ = 0.989 × 10^-9 m
EJ = 0.969 × 1.602 × 10^-19 J
Solve for φ. The result will be the work function of the surface material in joules.
Note: It's important to ensure that the units are consistent throughout the calculation. In this case, we are using meters for wavelength and joules for energy.