Question #4e709

1 Answer
Jun 2, 2016

9 maxima measured from the normal

Explanation:

The equation for determining the orders of maxima seen is:

#nlamda=dsintheta#

Where

#n#= order of maxima (0,1,2,3..)
#d#= separation of slits in grating=#1/(2times10^5)=5times10^-6m#
#theta# =the angle at which the interference patterns are seen (measured normal to the grating)

#lamda# =wavelength = #625times10^-9m#

The maximum angle(#theta#), that is possible is 90 degrees, and #sin90^0=1#

The largest possible order of maxima is therefore #nlamda=d#

So in this example:

#n*(625times10^-9)=(5times10^-6)#

#n=8#

Including the zero order this would give 9 maxima measured from the normal (in practice, 8 observed either side of the zero order central maxima)