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please answer the following physics questions!!! 1. You are helping your neighbo

ID: 1291036 • Letter: P

Question

please answer the following physics questions!!!

1. You are helping your neighbor with a science fair project with the goal of displaying the visible spectrum. You suggest that your neighbor use a diffraction grating in order to disperse the light over 30 degree in first order. A. How many lines per millimeter does your grating need? B. What is the first-order diffraction angle of light from a sodium lamp (lambda = 589 nm)? 2. The two strongest visible hydrogen lines are H-alpha (lambda = 656 nm) and H-beta (lambda = 486 nm). A hydrogen lamp illuminates a diffraction grating with 520 lines/mm. The diffraction pattern then appears on a screen 1.3 m behind the grating. What is the distance between the first order red and blue fringes?

Explanation / Answer


apply d sin theta = mL

d = 1 *(656 *10^-9)/(sin 30)

d = 1.312 um

No. of lines = 1/d   = 7600 lines per cm
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b. sin theta = 1* 589 nm /1.312 um)

sin theta = 0.448

theta = 26.67 deg
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2. here d = 1/520 = 1.92m um

Y2-Y1 = 1 *(656-486) nm * 1.3/(1.92 um)

DY = 0.115 m