Posted by McPhysics on .
Hello, we are doing a lab dealing with diffraction gratings. The problem I have is that we are supposed to find the number of slits, N, based on gathered information. I have x, L, d, m, and w, just not N, which is what I am trying to find. I also have the wavelength. Is this the right equation to use? dsintheta= mlambda and then reagrrange to find N, for d=(w/N) and sintheta= (x/L) so the equation for N would be to take mlambda and divide that by (x/L) which would be equal to w/n and then to find N you would divide out the w, but my answer won't work, it is way too small. Any ideas?

Physics Lab 
bobpursley,
check this algebra
w/N sinTheta= m lambda
N= w/(m lambda) * sinTheta
N= w/(m lambda) * x/L 
Physics Lab 
URGENT,
yes! It works I got an answer or 35.2 so there were approximately 35 slits! But wow, thanks soo much! This really saved me! I appreciate this!