Estimate the wavelength at which plasma reflection will occur for a metal having the density of electrons N≈4×1027m−3 Take ϵ0≈10−11 and m≈10−30, where these quantities are in proper SI units.
A
800 nm
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B
600 nm
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C
300 nm
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D
200 nm
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Solution
The correct option is C 600 nm ωp= √Ne2me0 = √4×1027×(1.6×10−19)210−30×10−11 ωp = 1.6×2×1015 f= ω2π = 0.5×1015 c=fw w= 3×1080.5×1015= 600nm