# In interference we put n=0 for first dark , in the formula [2n+1/2 ]lamda. why we put 0 here .in the formula [2n- 1/2 ]lamda we put n=1 .why?

Arun
25758 Points
2 years ago
because n =1 points out first fringe from the centre but zero tells us about the absolute centre.

Hope it helps
Vikas TU
14149 Points
2 years ago
Dear student
n = 0 points out the absolute centre .
n= 1 points out the first fringe from centre .
Usually we use the formula when n starts from 0 is:
((2n+1)/2) * Lambda
Hope this helps
Good Luck