- #1
ProPatto16
- 326
- 0
got a couple of questions...
firstly,
A blue supergiant star has surface temperature 29kK and has total power output 100000 times that of the Sun.
where is the wein peak of this stars balckbody curve?
I got lambda=9.99*10^-8m, which i know is right.
now, radius of sun is 6.96*108m, find radius of supergiant..
so ratio here should give the supergiant a surface area of A=100000A of sun.. solving for that gives r = 2.11*10^11m... but it tells me its wrong?
secondly,
A photoelectric experiment uses 265 nm light and a silver target.
Find max kinetic energy of photoelectrons.
Kmax=hf-W0
h=6.626*10-34
f=c/lambda=1.13*10^15
W0 for silver = 7.43*10^-19
subbing in gives Kmax = 5.738*10^-21J... and it also tells me that is wrong?
thirdly,
Suppose you want to observe neutron diffraction in a crystal with 0.28 nm spacing between lattice planes.
Find the momentum of neutrons having wavelength equal to this spacing.
found p=2.4*10^-24 kg*m/s
Find the kinetic energy of neutrons having wavelength equal to this spacing.
found K=1.7*10^.21 J
If these neutrons constituted an ideal gas, what would be the gas temperature?
How the heck do i do that :S??
thanksss so much for any help!
firstly,
A blue supergiant star has surface temperature 29kK and has total power output 100000 times that of the Sun.
where is the wein peak of this stars balckbody curve?
I got lambda=9.99*10^-8m, which i know is right.
now, radius of sun is 6.96*108m, find radius of supergiant..
so ratio here should give the supergiant a surface area of A=100000A of sun.. solving for that gives r = 2.11*10^11m... but it tells me its wrong?
secondly,
A photoelectric experiment uses 265 nm light and a silver target.
Find max kinetic energy of photoelectrons.
Kmax=hf-W0
h=6.626*10-34
f=c/lambda=1.13*10^15
W0 for silver = 7.43*10^-19
subbing in gives Kmax = 5.738*10^-21J... and it also tells me that is wrong?
thirdly,
Suppose you want to observe neutron diffraction in a crystal with 0.28 nm spacing between lattice planes.
Find the momentum of neutrons having wavelength equal to this spacing.
found p=2.4*10^-24 kg*m/s
Find the kinetic energy of neutrons having wavelength equal to this spacing.
found K=1.7*10^.21 J
If these neutrons constituted an ideal gas, what would be the gas temperature?
How the heck do i do that :S??
thanksss so much for any help!