Answer:
The value is [tex]\lambda = 572 *10^{-9} \ m[/tex]
Explanation:
From the question we are told that
The number of bright fringes is n = 402
The displacement of the mirror is [tex]\delta l = 0.115 \ mm = 1.15 *10^{-4} \ m[/tex]
Generally the number of fringes is mathematically represented as
[tex]n = \frac{2 * \delta l }{\lambda }[/tex]
=> [tex]\lambda = \frac{2 * \delta l }{n }[/tex]
=> [tex]\lambda = \frac{2 * 1.15*10^{-4} }{402 }[/tex]
=> [tex]\lambda = 572 *10^{-9} \ m[/tex]
