{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

# Q11S - 1 3 A compact way of writing the Bohr energy level...

This preview shows pages 1–2. Sign up to view the full content.

Quiz 11 Solutions Check the best answer. 1. The only experimental fact about the photoelectric effect that is consistent with classical theory is: If the incident light has frequency below a certain number, no electrons are released. [Should depend on intensity, not frequency.] The maximum kinetic energy of the released electrons rises linearly with the frequency of the incident light. [Same as above.] The maximum kinetic energy of the released electrons is independent of the intensity of the incident light. [Same as above.] The number of electrons released per second is proportional to the intensity of the incident light. [Number of photons per second is proportional to the intensity.] Check T or F depending on whether the statement is true or false. 2. If all the material in our solar system had been built up from light elements by fusion and neutron capture, we would find elements no more massive than iron. T F Physics 54 Summer 2011

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 1 3. A compact way of writing the Bohr energy level formula for hydrogen is E n = − α 2 mc 2 2 n 2 , where = ke 2 / c ≈ 1/137 is a dimensionless number, and m is the electron mass. Use the classical relations for a circular orbit: K = − 1 2 U , and U = − ke 2 / r for the electron-proton system. a. Derive the formula v n = c 1 n for the electron’s speed in the n th orbit. b. Derive the formula r n = mc n 2 for the radius of the n th orbit. c. Show from these that the angular momentum is given by L = n . a. Since K + U = E and U = − 2 K we see that K = − E , so we set 1 2 mv n 2 = 2 mc 2 2 n 2 and Fnd the claimed result. b. Since K + U = E and K = − 1 2 U we see that E = 1 2 U . We set − 2 mc 2 2 n 2 = − 1 2 ke 2 / r n = − 1 2 c / r n , and Fnd the claimed result. c. Since L n = mv n r n , we Fnd the claimed result. Physics 54 Summer 2011 2...
View Full Document

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern