# Radioactive decay plot, using Euler method of solving diff. equation
from pylab import *
t = 0.
dt = 0.1
L = .5 # decay constant
N = 10000.0 # Number of atoms at t = 0
ta = [t] # list for storing time
na = [N] # and instantaneous number of atoms
while t < 5:
dn = -L * N * dt
N = N + dn
t = t + dt
ta.append(t)
na.append(N)
plot(ta,na)
show()