The tube in a medical research X-ray unit uses platinum (Z=78) as it\'s target.
ID: 1401364 • Letter: T
Question
The tube in a medical research X-ray unit uses platinum (Z=78) as it's target.
1)
Use the Bohr model to estimate the minimum kinetic energy electrons must have to in order for K X-rays to just appear in the X-ray spectrum of the tube.
Ee =
eV
Your submissions:
80634.4
Computed value:
80634.4
Submitted:
Tuesday, July 28 at 2:59 PM
Feedback:
Correct!
2)
Assuming the electrons are accelerated from rest through a voltage, V, what is the minimum voltage necessary to produce the K X-rays?
V =
V
Your submissions:
80634.4
Computed value:
80634.4
Submitted:
Tuesday, July 28 at 3:23 PM
Feedback:
Correct!
3)
Assume the electrons are accelerated through the voltage calculated in part (2). What is the wavelength of the Kline?
=
nm
4)
Now assume that the electrons are accelerated through twice the voltage calculated in part (2). What is the wavelength of the K line?
=
nm
Questions 1 and 2 are correct. I confused on 3 and 4. Thanks!
Explanation / Answer
part 3 )
lambda = hc/eV
h = planck constant = 6.634 x 10^-34
c = speed of light light = 3 x 10^8 m/s
e = charge on electron = 1.6 x 10^-19
V = applied voltage
lambda = 1.54 x 10^-11 m
lambda = 0.0154 nm
part b ) lambda is inversly propotional to voltage if you make voltage twice then wavelength should be half
lambda = 0.0077 nm
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