Readings

Read Chapters 2 and 3 of The Inflationary Universe and Chapter 2 of the First Three Minutes

Homework 7

Due Friday April 9

1. Using the formula for the energy levels of the hydrogen atom , calculate with 2 significant digits, the frequency and the wavelength of a photon emitted for a transition from to . For precise values of the constants see the Particle Data Group
2. Suppose that the hydrogen atom emitting the light at a wavelength calculated in 1 is moving away from you at a speed v and that you measure the wavelength and obtain meter. From this, calculate v.
3. Using the gravitational constant G and the density gram per cubic centimeter, form a quantity having the dimension of a time and calculate its numerical value in years.

• About this document ...