In [1]:

```
#Wavelength of X-rays
h = 6.6e-034 # Planck's constant, J-s
V = 50000 # Potential difference, volts
c = 3e+08 # Velocity of light, m/s
e = 1.6e-019 # Charge of an electron, coulombs
L_1 = h*c/(e*V) # wavelength of X-rays, m
L = L_1/1e-010 # wavelength of X-rays, angstorm
print "The shortest wavelength of X-rays = %6.4f angstorm"% L
```

In [3]:

```
#Planck's constant
L = 24.7e-012 # Wavelength of X-rays, m
V = 50000 # Potential difference, volts
c = 3e+08 # Velocity of light, m/s
e = 1.6e-019 # Charge of an electron, coulombs
# Since e*V = h*c/L # Energy required by an electron to move through a potential barrier of one volt, joules
# solving for h
h = e*V*L/c # Planck's constant, Joule second
print "h = %3.1e Js "% h
```

In [5]:

```
#Short wavelength limit
V = 50000 # Potential difference, volts
h = 6.624e-034 # Planck's constant, Js
c = 3e+08 # Velocity of light, m/s
e = 1.6e-019 # Charge of an electron, coulombs
# Since e*V = h*c/L # Energy required by an electron to move through a potential barrier of one volt, joules
# solving for L
L = h*c/(e*V) # Short wavelength limit of X-ray, m
print "Short wavelength limit of X-ray = %6.4f angstorm"% (L/1e-010)
```

In [6]:

```
#Wavelength limit of X-rays
V = 20000 # Potential difference, volt
h = 6.624e-034 # Planck's constant, Js
c = 3e+08 # Velocity of light, m/s
e = 1.6e-019 # Charge of an electron, coulombs
# Since e*V = h*c/L # Energy required by an electron to move through a potential barrier of one volt, joules
# solving for L
L = h*c/(e*V) # Wavelength limit of X-rays, m
print "Short wavelength limit of X-ray = %6.4f angstorm"% (L/1e-010)
```

In [8]:

```
#Minimum voltage of an X-ray tube
h = 6.625e-034 # Planck's constant, Js
c = 3e+08 # Velocity of light, m/s
e = 1.6e-019 # Charge of an electron, coulombs
L = 1e-010 # Wavelength of X-rays, m
# Since e*V = h*c/L # Energy required by an electron to move through a potential barrier of one volt, joules
# solving for V
V = h*c/(L*e) # Potential difference, volts
print "The minimum voltage of an X-ray tube = %5.2f kV"% (V/1e+03)
```

In [10]:

```
#Minimum wavelength emitted by an X-ray tube
h = 6.625e-034 # Planck's constant, Js
c = 3e+08 # Velocity of light, m/s
e = 1.6e-019 # Charge of an electron, coulombs
V = 4.5e+04 # Accelerating potential of X-ray tube, volt
# Since e*V = h*c/L_min # Energy required by an electron to move through a potential barrier of one volt, joules
# solving for L_min
L_min = h*c/(V*e) # Minimum wavelength emitted by an X-ray tube, m
print "The minimum wavelength emitted by the X-ray tube = %5.3f angstrom"% (L_min/1e-010)
```

In [11]:

```
#Critical voltage for stimualted emission
h = 6.625e-034 # Planck's constant, Js
c = 3e+08 # Velocity of light, m/s
e = 1.6e-019 # Charge of an electron, coulombs
L_k = 0.178e-010 # Wavelength of k absorption egde of X-rays, m
# Since e*V_critical = h*c/L # Energy required by an electron to move through a potential barrier of one volt, joules
# solving for V_critical
V_critical = h*c/(L_k*e) # Crtical voltage for stimulated enission, volt
print "The critical voltage for stimulated emission = %4.1f kV"% (V_critical/1e+03)
```