In: Physics
A. What is the minimum wavelength of x-rays?
Knowns: 45 KeV at a tungsten target
B. an electron in hydrogen goes from n = 5 to the n = 3 energy level.
What wavelength of light is emitted?
A.
Energy of electrons,E=45keV=451.610-19 J
Also
E=hc/
So,minimum wavelength of X-ray is
=hc/E=(6.6310-343108)/(451.610-19 )=2.7610-8 m
B.
Energy of transition from one state to other in H-atom is
E=-13.6eV[1/(n1)2-1/(n2)2]
Also
E=hc/
n1=5 and n2=3
so
E=-13.6eV[1/(5)2-1/(3)2]=-13.61.610-19[1/(5)2-1/(3)2]=1.5510-19 J
So
Wavelength of emitted light is
=hc/E=(6.6310-343108)/(1.5510-19 )=1.2910-6 m