Question

calculate the kinetic energy of an electron ejected from a piece of sodium (φ = 4.41x10–19 j) that is illuminated with 285 nm light

Answer 1

First, let's calculate the energy of the
photon using the equation E = hc/%,
where:
- h is Planck's constant (6.62607015 ×
10-34 J.S)
- c is the speed of light in a vacuum (2.998 × 108 m/s)
- ^ is the wavelength of light (295 nm =
295 × 109 m)
E= (6.62607015 x 10-34 J.s × 2.998 × 108 m/s) / (295 × 10-° m)
E = 6.687 × 10-19 J
Now, to find the kinetic energy of the ejected electron, we subtract the work function (Ф) from the energy of the photon:
Kinetic energy = E - D
Kinetic energy = (6.687 × 1019 J) - (4.41 x
10-19 J)
Kinetic energy = 2.277 × 10-19 J
Therefore, the kinetic energy of the electron ejected from sodium when illuminated with 295 nm light is approximately 2.277 × 1019 J.