HSC · Physics · Light: Wave Model live from the app

Diffraction and Polarisation (Malus' Law)

Two behaviours only waves can pull off: bending around obstacles and being filtered by orientation. Diffraction and polarisation are light's wave credentials - and Malus' law makes the second one quantitative. This is the real knowscape from knowhere, not a picture of one. Drag it. Watch what actually changes.

physics · light: wave model · diffraction and polarisation (malus' law)drag it · it is yours
in the wild

Diffraction works like sound leaking past a doorway.

Light behaves like a wave, and every phenomenon here is a bet on that: diffraction spreads it, polarisation filters it by orientation, and Malus's law counts what survives. Newton called light particles and lost this round — because only waves bend around edges and dim by cos-squared through a filter.

The music sits packed at the doorway, a single narrow gap to the next room.

Sound spills through and bends around the edges instead of going straight.

Waves spread wide across the whole room — a narrower gap spreads more.

what examiners catch — Students often forget that Malus' Law requires the incident light to already be polarised, or they incorrectly apply it when light passes through the first polariser which simply halves the intensity.
what you leave with

five things, not forty.

what's underneath

nothing. this is where it starts.

This concept has no prerequisites in knowhere's map — it is a root. Everything in the topic is built from here.

this conceptdiffraction and polarisation (malus' law)Diffraction shows light spreads through gaps and around edges while polarisation filters light by orientation, with Malus' Law stating transmitted intensity equals incident intensity times cosine-squared of the angle between polariser axes.
the rest of light: wave model

3 more, same treatment.

Each one is its own knowscape in the app — built for how a particular student takes things in, not one explanation handed to everybody.

interference and path differencein the appnewton vs huygens: competing models of lightin the appyoung's double-slit experimentin the app
this is one of 865

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