Light and matter quiz

Gamma radiation is often used to treat cancerous tumours. The energy of a gamma photon emitted by radioactive cobalt-60 is 1.33 MeV. Which one of the following is closest to the frequency of the gamma radiation?

• λ = 440 nm

• λ = 220 nm

• λ = 660 nm

• λ = 880 nm

Determine the momentum of a photon with energy 4.52 × 10⁻³⁴ J.

• 1.50 × 10⁻²⁷ N s

• 3.00 × 10⁻²⁸ N s

• 2.26 × 10⁻³⁰ N s

• 6.63 × 10⁻³² N s

Determine the energy of one photon of light emitted by a laser with a wavelength of 580 nm.

• 3.43 × 10⁻¹⁹ J

• 2.15 × 10⁻¹⁹ J

• 4.98 × 10⁻²⁰ J

• 1.12 × 10⁻¹⁸ J

Students are studying the photoelectric effect using the apparatus shown in the figure. The following graph shows the results the students obtained for the maximum kinetic energy (E_k max) of the emitted photoelectrons versus the frequency of the incoming light. a. Using only data from the graph, determine the values the students would have obtained for i. Planck’s constant, h. Include a unit in your answer

• h = 5.3 x 10^15 eV s

• h = 4.15 x 10^15 eVs

• h = 5.3 x 10^15 Js

• h = 1.89 x 10^14 eVs

The maximum wavelength of light that would cause the emission of photoelectrons.

• λ_max = 810 nm

• λ_max = 400 nm

• λ_max = 1200 nm

• λ_max = 250 nm

The work function of the metal of the photocell.

• ϕ ≈ 1.9 eV s

• ϕ ≈ 0.5 eV s

• ϕ ≈ 3.2 eV s

• ϕ ≈ 5.0 eV s

If the work function of the metal in the photocell is changed from ϕ to (1/2)ϕ, how would the line on the graph shift?

• The line would shift to the left, with the x-intercept occurring at a lower frequency.

• The line would shift to the right, with the x-intercept occurring at a higher frequency.

• The line would remain unchanged.

• The slope of the line would decrease.

The diagram below shows a plot of maximum kinetic energy, Ek max, versus frequency, f, for various metals capable of emitting photoelectrons. Which one of the following correctly ranks these metals in terms of their work function, from highest to lowest in numerical value?

• sodium, potassium, lithium, nickel

• nickel, potassium, sodium, lithium

• potassium, nickel, lithium, sodium

• lithium, sodium, potassium, nickel

Using the students’ measurements, what value would they calculate for Planck’s constant? Outline your reasoning and show all your working. Give your answer in joule-seconds.

• h = 4.9 × 10⁻³⁴ J s

• h = 6.6 × 10⁻³⁴ J s

• h = 3.2 × 10⁻³⁴ J s

• h = 1.1 × 10⁻³⁴ J s