All of the 28 boys in an Australian school class play either Australian Rules football or soccer. 13 of the boys are migrants and 9 of these 13 play soccer. Of the remaining 15 boys, 4 play soccer. A boy is selected at random and plays Australian rules. Find the probability that he is a migrant.

Consider electrons accelerated to a total energy of 20.0 GeV in the 3.00-km-long Stanford Linear Accelerator. How long does the accelerator appear to the electrons? Electron mass energy: 0.511 MeV.

Red light of wavelength 670 nm produces photoelectrons from a certain photoemissive material. Green light of wavelength 520 nm produces photoelectrons from the same material with 1.50 times the maximum kinetic energy. What is the material’s work function?

Protons in an accelerator at the Fermi National Laboratory near Chicago are accelerated to a total energy that is 400 times their rest energy. What is the speed of these protons in terms of c?

Suppose a star with radius $8.50 \times 10 ^ { 8 }$ m has a peak wavelength of 685 nm in the spectrum of its emitted radiation. At what rate is energy emitted from the star in the form of radiation? Assume the star is a blackbody (e = 1).

Suppose a star with radius $8.50 \times 10 ^ { 8 }$ m has a peak wavelength of 685 nm in the spectrum of its emitted radiation. Find the energy of a photon with this wavelength.

Compute the derivative of the given function and find the equation of the line that is tangent to its graph for the specified value x = c. $f(x)=\frac{1}{x^{3}};$ c = 1

A sodium surface is illuminated with 305 nm light. Determine the energy of each photon in joules.

Rigel, a bluish-white star in Orion, radiates with a peak wavelength of 145 nm. Find the temperature of Rigel’s surface.

If the average energy released in a fission event is 208 MeV, find the total number of fission events required to operate a 100-W lightbulb for 1.0 h.

B. Radiation emitted from human skin has its peak intensity at $\lambda=940 \mu \mathrm{m}$. How much energy in electron volts is carried by one quantum of this radiation? Hint: $E=h f=h \frac{c}{\lambda}$

Tritium has a half-life of 12.33 years. What fraction of the nuclei in a tritium sample will remain after 5.00 yr? Discuss whether that is realistic.

Green light is emitted when electrons in a substance make a particular energy-level transition. If blue light were instead emitted from the same substance, would it correspond to a greater or lesser change of energy in the atom?