Question

If a cloud lying between a star and an observer has an average absorption coef- ficient of a = 3.0 x 10-13cm-1 (that varies throughout the cloud), a thickness of s = 2.0 x 1013cm and an optical depth of t = 7 along the line of sight, the intensity of the light will be: (a) reduced by a factor of e-3.0x10", (b) reduced by a factor of 3.0 x 10-13 (c) reduced by a factor of e-6, (d) reduced to zero, (e) reduced by a factor of e-> (f) not enough information, one needs to know the details of how the density varies along the line of sight.

If a cloud lying between a star and an observer has an average absorption coefficient of a = 3.0 x 10^-13 cm^-1 (that varies throughout the cloud), a thickness of s = 2.0 x 10^13 cm and an optical depth of t = 7 along the line of sight, the intensity of the light will be: (a) reduced by a factor of e^-3.0x10", (b) reduced by a factor of 3.0 x 10^-13 (c) reduced by a factor of e^-6, (d) reduced to zero, (e) reduced by a factor of e^-7 (f) not enough information, one needs to know the details of how the density varies along the line of sight.

Answer 1

since optical depth XE 3.0x lol 3.0x1013 (0) - 20x1013 em T = Sads = (sads = 2575 = x [2.0 x10 cm-o] -13 13 - 3.0x10 cm x 2.0X10 cm but given that optical depth = 7 so there are conpadictians Acatally we can not ealitat T = 2ds untill we don't know Ext) T=T(S) so taken I will be 7. It is longer be case there may be even self abscoftian by cloud so I - Is e -7 - Ise so light intensity will be reduced by e 7 option no is cont