Problem 1:

Red light has a wavelength () of 590 nm.

(a) What is its frequency? (b) What is its energy?

(c) What is this value in wavenumbers (defined as 1/ typically with units of cm− which is the number of waves that fit in a 1 cm length)

(d) Can orange light break a carbon-carbon bond in DNA? How about UV light with a wavelength of 260 nm? (carbon-carbon bond energies are typically around 335 kJ/mol)

Problem 2:

Determine the energy (in Joules) associated with the transition of 3 mol of photons following electronic transitions from n = 6 to n = 3 in atomic hydrogen

Problem 3:

(a) Use Bohr’s model to calculate the energy required to ionize atomic beryllium. (b) Comment on the discrepancy between your calculated value and the experimentally determined

value (9.2 eV). Describe how you might account for any difference quantitatively.

Problem 4:

The work function of chromium metal is 4.4 eV.

(a) Calculate the kinetic energy of electrons emitted from a chromium surface when it is irradiated with ultraviolet radiation of wavelength 2000 Å.

(b) What is the stopping potential (c) If the chromium is irradiated with light of varying wavelengths, from 2000 Å up through the full

visible spectrum, make a plot of kinetic energy (eV) of the emitted electrons vs. frequency (x 1014 Hz) of incident radiation

(d) What is the velocity of the fastest moving ejected electron in this experiment. Do you think it’s okay to ignore relativistic effects at this velocity? (Hint: typically you can ignore relativistic effects if the velocity is less than 10% of the speed of light)