# Homework Help: Diffraction hw help

1. Feb 1, 2008

### physicsbhelp

[SOLVED] Diffraction hw help

1. The problem statement, all variables and given/known data

calculate d for a diffraction grating with 600 lines/mm.

2. Relevant equations

mwavelength / d = x/ L

3. The attempt at a solution

well i really don't know what to solve for because i thought the diffraction grating is d.

2. Feb 1, 2008

### physicsbhelp

how would you solve for d?

3. Feb 1, 2008

### hage567

What is d supposed to be? (what does it represent)

4. Feb 1, 2008

### physicsbhelp

d= gap separation

5. Feb 1, 2008

### physicsbhelp

or maybe it means put it in terms of m/lines?

6. Feb 1, 2008

### hage567

Gap separation would be expressed in units of length, right? So if there are 600 lines per mm, how many mm is one line?

7. Feb 1, 2008

### physicsbhelp

1.66 * 10-3 mm/Line ? is that right and then can i change it to meters to be 1.66* 10-6 m/line

8. Feb 1, 2008

### hage567

That's how I would do it. I don't know if you need to convert to meters but there's nothing wrong with that.

9. Feb 1, 2008

### physicsbhelp

the portion of the equation x/L is the same as oppostie/hypotenuse so the orginal equation can be written as sin (theda) = m*wavelength / d. Since sin (theda) cannot exeed 1 what is the highest order bright line which can be formed form the 6330 Anstrom (spelling of this unit is probably wrong) laser upon the 600 lines/mm diffraction grating?

i worked the problem and for the answer i got:
the 2nd order?

10. Feb 1, 2008

### hage567

Looks OK to me.