No.of orders of diffraction visible

[Janiceleong26]

1. Homework Statement

Homework Equations

dsinθ=nλ

The Attempt at a Solution

I chose D, but I can't seem to see why the number of orders changes. There are more lines per metre, so distance between slits decreases, hence sinθ would increase, which means θ increases too. But this would only apply if the number of diffraction orders and the wavelength is the same, according to the formula. Why does the number of diffraction order changes? The answer is B

 

[Dr. Courtney]

How many can fit between + pi/2 and - pi/2?

 

[Janiceleong26]

How many can fit between + pi/2 and - pi/2?

2d/λ ?

 

[Janiceleong26]

How many can fit between + pi/2 and - pi/2?

Ohhh, so as distance between slits, d, reduces, n reduces, ok I got it. Thanks!