Line 21 giving me troubles

Could someone help please? Having errors with line 21 for "Time". 




%This program will calculate the approximate time for electrons to travel 
% from cathode to anode of a rectifier tube.
%
clear
clc
%Get user input
min_V=input('Enter the min limit of accelerating voltage:');
max_V=input('Enter the max limit of accelerating voltage:');
r1=input('Enter the radius of the inner tube (cathode) in mm:');
r2=input('Enter the radius of the outer tube (anode) in mm:');
%
%
V=(min_V:1:max_V);
%Range of voltage 1-10, increments 1
z=log(r2./r1);
%Natural Logarithm of R2/R1
q=1.60206*10^-19;
%Charge of electron in coulombs
m=9.1083*10^-31;
%Mass of electron in kilograms
time=z*r1*(sqrt((2*m)/(q.*V)))*(1+(z/3)+(z^2/10)+(z^3/42)+(z^4/216));
%Time for electron to travel from cathode to anode (in sec)
%
%
%
%
%Display output as required
my_results=[V',time'];
disp('         ');
disp('Voltage Time');
disp('-------- ------');
disp('(volts)  (seconds)');
disp(my_results);
%
%End of file

Answer 1

[David Hill]

time=z*r1*(sqrt((2*m)./(q*V)))*(1+(z/3)+(z^2/10)+(z^3/42)+(z^4/216));%just need ./ since V is an array

[azaandria]

Thank you. That did help partially. But something is still wrong with my formula. Its calculating 0.00 seconds for every volt. I will review my calculations. Thanks!

Enter the min limit of accelerating voltage:

1

Enter the max limit of accelerating voltage:

10

Enter the radius of the inner tube (cathode) in mm:

2

Enter the radius of the outer tube (anode) in mm:

4

Voltage Time

-------- ------

(volts) (seconds)

1.0000 0.0000

2.0000 0.0000

3.0000 0.0000

4.0000 0.0000

5.0000 0.0000

6.0000 0.0000

7.0000 0.0000

8.0000 0.0000

9.0000 0.0000

10.0000 0.0000

[David Hill]

It is working. Time is of the order of 10e-6, so the display is zero. Try:

plot(V,time);