The photoelectric work function (circle with line through it symbol) is the minimum energy needed to eject and electron

Question

from the metal by irradiating it with light. Determine the speed (in meters per second) of the ejected electron when light of the wavelength 187.5nm Shines on a piece of magenisuim metal? The work function for magnesium is 5.90 x 10 ^-19 J. The mass of the electron is 9.1094 x 10 ^-31 kg. (answer in scientific notation to 3 sig figs and units

Answer 1

E_k=hf-Φ

E_k=kinetic energy h=planks constant(6.626E-34) f=frequnecy Φ=work function

f=c/λ

c=speed of light(2.998E8) λ =wavelength

f=(2.998E8)/(187.59E-9)=1.598E15 hz

E_k=(6.626E-34)(1.598E15)-(5.9E-19)=4.689E-19J

E_k=1/2mv²

m=mass v=velocity

4.689E-19=(1/2)(9.1094E-31)v²

1.01E6 m/s