General Astronomy, 29:61
Fall, 2004
Ninth Homework Set...November 10, 2004.
Due November 19, 2004

Note: There will be no office hours on Tuesday, November 16, and only afternoon hours on Thursday, November 18. It would be smart to look at these tonight and talk to me during Thursday office hours tomorrow, November 11

(1): Calculate the mean density of Jupiter and Saturn. Compare the value with that of the Earth.

(2) A electron is moving with velocity

$$\vec{v} = 0\hat{e}_x + V \hat{e}_y + 0 \hat{e}_z$$ (1)

in a magnetic field given by

$$\vec{B} = 0\hat{e}_x + 0\hat{e}_y + B_0\hat{e}_z$$ (2)

Does it move to the right (towards positive $x$) or to the left (towards negative $x$)? Explain your answer. The electric charge of an electron is $-1.6 \times 10^{-19}$ Coulombs.

(3) The surface of Titan has a temperature of 90K. At what wavelength will its emitted blackbody radiation be brightest?

(4) Calculate the equilibrium surface temperature for Titan, ignoring the effect of its atmosphere. Show your work. Remember that the solar constant, which is 1370 W/m$^2$ at the Earth, is inversely proportional to the distance of an object from the Sun.

(5) Would you expect the number calculated in #4 to be larger, smaller, or the same as the surface temperature given in problem # 3? Explain your answer.