Suppose dust opacity scales with 1/λ. If a cloud has an optical depth τ=10 at wavelength λ=500 nm, how many magnitudes o

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Suppose dust opacity scales with 1/λ. If a cloud has an optical
depth τ=10 at wavelength λ=500 nm, how many magnitudes of
extinction in optical (AV) at λ=500 nm and IR (AIR) with λ=5 μm? A.
AV=10 ; AIR=10 B. AV=1 ; AIR= 10 C. AV= 11 ; AIR= 1.1 D. AV= 1.1 ;
AIR= 11 E. AV= 10 ; AIR= 5
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