Answer:
0.126mm
Explanation:
To find the distance to the central bright spot you can use the following formula:
[tex]y=\frac{m\lambda D}{d}[/tex]
y: distance from the m-bright spot to the central one.
m: order of the bright (in this case, the second order, m=2)
D: distance to the scree = 1.6m
d: distance between slits = 17mm = 17*10^{-3}m
By replacing the values of m, D, d and the wavelength you obtain:
[tex]y=\frac{(2)(670*10^{-9}m)(1.6m)}{(17*10^{-3}m)}=1.26*10^{-4}m=0.126mm[/tex]
hence, the ditance from the second order fringe to the central spot is 0.126mm