- #1
trina1990
- 24
- 0
the energy output of a star is such at the surface of the Earth it provides 5x10^-19 WM^-2 in the visible part of the spectrum...
how many photons are collected per second by a 500mm diameter telescope?
i don't know if there's any definite formula to drive the answer...but i tried this way..
stellar flux=5x10^-19WM^-2=5x10^-25 J/S/mm^2
E=hc/lambda joul/photon ( assuming lambda to be 550nm)
then flux/E=1.383x10^-6 photon /S/mm^2
then i found the telescope mirror are to be 4pi (500)^2=3.142x10^6 mm^2
now i derived the number of photons per second collected by the 500mm diameter to be 4.4!
can this be right?
is there any other way to solve this?
how many photons are collected per second by a 500mm diameter telescope?
i don't know if there's any definite formula to drive the answer...but i tried this way..
stellar flux=5x10^-19WM^-2=5x10^-25 J/S/mm^2
E=hc/lambda joul/photon ( assuming lambda to be 550nm)
then flux/E=1.383x10^-6 photon /S/mm^2
then i found the telescope mirror are to be 4pi (500)^2=3.142x10^6 mm^2
now i derived the number of photons per second collected by the 500mm diameter to be 4.4!
can this be right?
is there any other way to solve this?