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A diffractiongratingconsisting of 4000 slitsper centimeter is illuminated with a monochromatic light that produces the second orderdiffraction at an angle of 30 ^(@). What is the wavelenght of the light used? |
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Answer» Solution :Number of lines per cm `=4000, m=2,0=30^(@),lambda=?` Number of lines per unitlength, `N=(4000)/(1xx10^(-2))=4xx10^(5)` Equation for DIFFRACTION maximumin GRATING is, `SIN0=Nmlambda` Rewriting, `lambda = (sin0)/(Nm)` Substituting, `lambda=(sin30^(@))/(4xx10^(5)xx2)=(0.5)/(4xx10^(5)xx2)=(1)/(2xx4xx10^(5)xx2)=(1)/(16xx10^(5))` `lambda=6250xx10^(-10)m=6250Å` |
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