Questions and comments .....

	1. For the subpart 11, part 1, you'll have a graph of y vs. x,
	   (where y = Y/n   and   x = 1/a.) When finding the slope, make
	   sure that you find the slope of the best-fit line. Explain how
	   you draw the best fit line. find an uncertainty in the slope.
	   ( Think about what is meant by "best-fit line" and using that
	   find a method for getting the uncertainty. Exxplain the method
	   you use.) Using this, find an uncertainty in wavelength   .

	2. Part 2 says "for each grating, repeat part 1". This includes
	   the calculations and plotting the graph. (You might skip the
	   uncertainty calculations.)(Make sure you use proper value of 
	   (1/a) , with correct units.)
	
	3. For the last part, "sketch the pattern" means dray a graph of
	   Intensity vs. distance. For example --















	4. Look successively at patterns for 1 slit, then 2 slits, then
	   3 slits then 4 slits then 5 slits...... and try to guess a 
	   regularity/pattern (in terms of how many small maxima are seen
	   between two big ones etc etc.). Using these observations, can
	   you reason why the pattern for a grating looks like it does??
	   ( Note : A grating pattern is basically a pattern obtained from
	            very large number ( about 100-500 ) of slits. )