You are correct! The luminosity is in fact 2,7 * 10^31 W for Rigel giving it a solar radii of 73 using my formulas.
However, I have to do this for a second star as well, Procyon B.
Calculating its solar radius with the same formulas using H = 2,1 * 10^23W and T = 10000K I get:
A = 3,7 *...
A student produces heat with a rate of 100W. How much heat is transferred from 90 students to a classroom in 50 minutes?
Attempt at solution:
100W (100 J/s) * 90 students * 3000 seconds = 2,7 * 10^7 J. Does this make sense?
The classroom is 3200 cubic meters and the air in it has a...
A star's surface sends out energy in form of electromagnetic radiation and has an emissivity close to 1. Find the solar radius of Rigel that emits energy at a rate of 2,7 * 10^32W and has a surface temperature of 11000K. You may assume the star is spherical.
Attempt at solution:
Formula for...
If we make an NPN transistor and change the base doping level so that we get a higher consentration of holes will β increase or decrease? Why?
I know β=IC/IB. Will more holes in the base make more electrons pass from the emitter to the collector increasing IC and thereby β? Or will IB...
I must have missed something basic because I still can't wrap my brain around this.
Here is how I see it (and this is probably very wrong since I know next to nothing about this):
Current from the first power source with the voltage U1 can go through resistor 6+4 OR 6+R OR 8. If I put this...
http://img5.imageshack.us/img5/6889/imagepf.jpg
I need to create a formula using R (resistance), U1 and U2 (voltage) for the current flowing through the 8 Ohm resistor. I've been looking at this for hours now and I still don't even know where to begin. Can anyone get me started on this?