The work function for a photosensitive metal is 1.5 ev. the metal is illuminated with a light of wavelength 500 nm. find: (a) maximum kinetic energy of the emitted electrons (b) maximum speed of the emitted electron, and (c) stopping potential

A) We want to find the maximum kinetic energy of the photoelectrons.

E = 1243/λ - Φ

E = kinetic energy of photoelectrons, λ = light wavelength, Φ = work function

Given values:

λ = 500nm, Φ = 1.5eV

Plug in and solve for E:

E = 1243/500 - 1.5

E = 0.986eV

B) We want to find the maximum speed of the photoelectrons.

KE = 0.5mv²

KE = max kinetic energy, m = electron mass, v = max speed

Given values:

KE = 0.986eV = 1.58×10⁻¹⁹J, m = 9.11×10⁻³¹kg

Plug in and solve for v:

1.58×10⁻¹⁹ = 0.5(9.11×10⁻³¹)v²

v = 5.89×10⁵m/s

C) We want to find the stopping potential for the photoelectrons:

Vq = E

V = stopping potential, q = electron charge, E = max kinetic energy of photoelectrons

Given values:

q = e (elementary charge), E = 0.986eV

There isn't much work to do to find V. The energy E is already given in electron-volts which is defined as the amount of energy an electron gains when passed through a 1V potential difference. All you have to do is remove the "e" from "eV" and you'll have your answer.

V = 0.986V

igneous rocks also form where plates converge. the subducting plate melts as it sinks into the crust of the earth, and the melt rises into the overriding plate forming volcanoes. metamorphic rocks are formed mainly in the lithosphere, wherever there is high pressure and high temperature. -woods