Visual Guide

YDSE Fringe Pattern — Inline SVG

$S_{1}$ $S_{2}$ d D → Screen y=0 β YDSE — Fringe Pattern β = λD/d

Single Slit Diffraction vs YDSE — Comparison Table

Feature	YDSE (Interference)	Single Slit (Diffraction)
Number of apertures	2 slits, separation $d$	1 slit, width $a$
Central fringe width	$\beta = \lambda D/d$ (same as all fringes)	$2\lambda D/a$ (twice secondary maxima)
Secondary fringe width	$\beta$ (all equal)	$\lambda D/a$ (half central)
Minima condition	$d\sin\theta = (2n-1)\lambda/2$	$a\sin\theta = n\lambda$
Maxima condition	$d\sin\theta = n\lambda$	$a\sin\theta = (2n+1)\lambda/2$
Intensity pattern	All maxima equal ( $I_{\max} = 4I_0$ )	Central brightest; secondary maxima fall rapidly

Brewster Angle Geometry

At Brewster's angle $\theta_p$ (where $\tan\theta_p = n$ ), the reflected ray is perpendicular to the refracted ray. The reflected ray is completely plane-polarized with $\vec{E}$ perpendicular to the plane of incidence. The refracted ray is partially polarized.

Polarization apparatus reference (Brewster angle demonstration): Brewster angle polarization

Malus's Law — Intensity Variation

Angle $\theta$ between polarizer and analyser	Transmitted intensity
$0°$	$I_0$ (maximum, axes aligned)
$30°$	$3I_0/4$
$45°$	$I_0/2$
$60°$	$I_0/4$
$90°$	$0$ (crossed polaroids)

NoteTube

Visual Guide

YDSE Fringe Pattern — Inline SVG

Single Slit Diffraction vs YDSE — Comparison Table

Brewster Angle Geometry

Malus's Law — Intensity Variation

YDSE Path Difference — Mermaid Flowchart