Diffraction

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DIFFRACTION: The spreading of waves when they pass through an opening or round an obstacle.

When waves pass through a gap, they can 'spread out' [ //or diffract// ]. If a wavelength is about the same size with the width of a gap, then it diffracts more. The wider the gap is, the less the diffraction is.

RIPPLE TANK SIMULATION WITH MANY OPTIONS

AN APPLET WHICH DEMONSTRATES SINGLE SLIT DIFFRACTION: DIFFRACTION Diffraction can be understood with reference to Huygen's secondary wavelets or you can consider the different distances that rays diffracted by an object take.

** Diffraction at a single slit **
Hotlinks - Single slit diffraction Double Slit Interference intro Double Slit Interference 1.Two slit interfernce 2.Single slit diffraction 3.Two slit with diffraction

Sketch the variation with angle of diffraction of the relative intensity of light diffracted at a single slit.

Derive the formula θ = λ/b for the position of the first minimum of the diffraction pattern produced at a single slit.

On the diagram below, the path difference is λ/2 for a minimum. sinθ = λ/a. Using small angle approximation and IB notation, θ = λ/b
 * [[image:nothingnerdy:diffraction_minima_calculated.gif caption="Slit width is a here, in IB equation it is b"]] ||
 * Slit width is 'a' here, in IB equation it is 'b' ||

Solve problems involving single-slit diffraction.

OBSERVE DIFFRACTION IN WATER, SOUND AND LIGHT ON THIS SIMULATION: [|PHET Wave Interference simulation]

DIFFRACTION APPLET

e.g. radio-waves around the mountains(o), telecommunication using mobile phone(x), light behind a pillar(x), sound around the corner or next to the door(o)
 * Waves diffract in a right condition.**

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