Question

A 0.50mm -wide slit is illuminated by light of wavelength 500nm .

What is the width of the central maximum on a screen 2.0m behind the slit?

Express your answer using two significant figures.

Answer 1

In interfreence or diffraction pattern

the needed equation is Y = mLR/d---------------1

and d sin theta = mL--------------------2

where L = wavelgnth

m = order = 1,2,3,4, ......... for brigth bands

m = 1.5, 2.5, 3.5, 4.5, ......for dark bands

R is the distance from slit to screen

Y = disatnce from central spot to nth order fringe or fringe width

-------------------------------------------------------------------

so here width 2Y = 2*1* 500nm * 2/0.5mm

2Y= width = 4 um