SPM : Light Interference

For light intereference, u must be able to describe what u’ve observed while doing the experiment. But majority of my student didn’t do the experiment..may b cikgu u all quite bz

..so here I am to explain the important observation need to be understood…

First..lets look at this experiment diagram..

From this experiment, we can measure the wavelength..but please watch out!..

the distance D =3m, not 3+1 m.

Now look at the next diagram..

Important things to observe from the diagram….

i. on the screen a uniform bright + dark fringes are formed

ii. bright fringes(white) = constructive interference

iii. dark fringes(black) = destructive interference

iv. x = is the distance between 2 bright fringes

v. a= distance between double slits ( i.e coherent sources)

To find wavelengh ,..again we apply

λ = ax

D

Ok..one more thing, u must be able to differentiate the fringes pattern between diffraction & interference…

(* famous in SPM)

(interference pattern)

.............look & Compare........

(diffraction pattern)

I leave u guys with this video..some might not covered in our SPM syllabus, but have a think about it..