CODEWITHSUNDEEP
pythonpython-3.xmatplotlibphysics
raylyn
raylyn

Reputation: 63

Plotting the electron deflection between plates of the capacitor in python

I want to plot the deflection of electron and all it shows no graph when i compile the program. This is my code so far and the comments represent the SI units.

import matplotlib.pyplot as plt

v=25300000 # m/s
E=1000 # V/m
d=10 # m
m=9*pow(10,-31) #kg 
q=1.6*pow(10,-19) # C

for i in range(0,d):
  y=(q*E*i*i)/(2*m*v*v)
  plt.plot(i,y)

plt.xlabel("x")
plt.ylabel("y")
plt.show()

Upvotes: 2

Views: 308

Answers (2)

William Miller
William Miller

Reputation: 10328

plt.plot requires more than one point (unless you specify a marker), so

plt.plot(i,y)

will not produce a graph when i and y are individual values, only if they are arrays or array-like objects. You can either replace this with plt.scatter,

import matplotlib.pyplot as plt

v=25300000 # m/s
E=1000 # V/m
d=10 # m
m=9*pow(10,-31) #kg 
q=1.6*pow(10,-19) # C

for i in range(0,d):
  y=(q*E*i*i)/(2*m*v*v)
  plt.scatter(i,y)

plt.xlabel("x")
plt.ylabel("y")
plt.show()

Which will give you

enter image description here

or to make a list of the y and x values,

y = []
x = []
for i in range(0, d):
    y.append((q*E*i*i)/(2*m*v*v))
     x.append(i)

plt.plot(x,y)

Or, even better, make x and y numpy arrays:

import numpy as np
# ...
x = np.arange(0,10)
y = (q*E*x**2)/(2*m*v*v)
plt.plot(x,y)

Either of which will give you

enter image description here

Upvotes: 3

jimsu2012
jimsu2012

Reputation: 170

I think you are looking for a scatter plot. plt.plot plots a curve instead. To make a scatter plot, you group the x and y coordinates into lists and call plt.scatter:

import matplotlib.pyplot as plt

v=25300000 # m/s
E=1000 # V/m
d=10 # m
m=9*pow(10,-31) #kg 
q=1.6*pow(10,-19) # C

x_list = []
y_list = []

for i in range(0,d):
  y=(q*E*i*i)/(2*m*v*v)
  x_list.append(i)
  y_list.append(y)

plt.xlabel("x")
plt.ylabel("y")

plt.scatter(x_list, y_list)

plt.show()

Upvotes: 1

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