# Physics - Quantum Mechanics - Photons

Please help with the following problems.

(1) Suppose that a photon has energy of 5 x 10 -19 J. (five times ten to the negative 19th Joule) What's the wavelength of this photon? What is its frequency?

(2) The photon in the above problem strikes a metal plate that has a work function of PHI = 3 x 10 ^ -19 J. What's the maximum kinetic energy of the ejected electrons? What's their maximum speed? (Use mass of an electron is 9.11 x 10^ -31 kg.)

(3) If a photon of λ = 300 nm strikes a metal with PHI= 7 x 10 -19 J,

Will any electrons be ejected? Explain.

https://brainmass.com/physics/work/physics-quantum-mechanics-photons-218332

#### Solution Preview

(1) Suppose that a photon has energy of 5 x 10 -19 J. (five times ten to the negative 19th Joule) What's the wavelength of this photon? What is its frequency?

Energy of a photon is given by E = hf, where h = Planck's constant = 6.63 x 10^ -34, and f = frequency of the photon.

Here, 5 x 10^ -19 = 6.63 x 10^ -34 x f

So, f = 7.54 x 10^14 Hz. ...

#### Solution Summary

This solution helps with quantum mechanics problems. A Complete, Neat and Step-by-step Solutions to the Problems is provided.