The Sun’s total energy output is 3.85×1026 watts, and 1 watt…

The Sun’s total energy output is 3.85×1026 watts, and 1 watt is 1 Joule/second. Assume 4.3×10−12 J is released from each proton–proton chain of reactions. Use the energy yield from the proton–proton chain to determine how many proton–proton chain fusion cycles must be happening each second in the solar core. 

Yesterday you installed a new game on your computer. When yo…

Yesterday you installed a new game on your computer. When you ran the computer, you noticed that the application was running very slow. After you exited the game and restarted it, you received an error message saying, “Insufficient memory or disk space.” You checked your hard drive and saw that you had more than 250GB of free space.   What should you check next in Task Manager?

The figure below shows the H-R diagram of a star cluster. Ho…

The figure below shows the H-R diagram of a star cluster. How old is it? (The dashed line is the position of the stars. The solid line is the main sequence.) You can estimate the life of a main-sequence star by using t = 1010 M/L years (M and L in solar units).