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Key areas. Maxima and minima are produced when the path difference between waves is a whole number of wavelengths or an odd number of half wavelengths respectively. Carry out calculations on the above. What we will do today:. Identify interference patters for both maxima and minima.
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Key areas • Maxima and minima are produced when the path difference between waves is a whole number of wavelengths or an odd number of half wavelengths respectively. • Carry out calculations on the above.
What we will do today: • Identify interference patters for both maxima and minima. • Carry out calculations on the above.
Maxima • In an interference pattern formed by two coherent sources, maxima occur at points of constructive interference: • Path difference = nλ for maxima where n is an integer, λ is the wavelength i.e. path difference = λ, 2λ, 3λ, etc. • Note - the space between each maxima is equal to one wavelength.
Minima • Minima occur at points of destructive interference: • Path difference = (n+½)λ for minima • i.e. path difference = ½λ, 1½λ, 2½λ, etc.
Example • Find the wavelength of the waves used below if the second off-centre maximum occurs at A: • Path difference = 36 – 24 = 12cm; n = 2 • For maxima: path difference = n λ • λ = path difference / n = 12 / 2 = 6cm
Multi-Ch: 2000 – 14 2001 – 15 2004 – 14 2008 – 14 Section B 2003 – 28 2010 - 27 Old Higher Past Paper Questions
Questions • Class jotter • Qu’s: 6 - 8