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A Carnot engine takes `3xx10^6` cal of heat from a reservoir at `627^@C` and gives it to a sink at `27^@C`. The work done by the engine is:A. `4.2 xx 10^(6)J`B. `8.4 xx 10^(6)J`C. `16.8 xx 10^(6)J`D. zero |
Answer» Correct Answer - B `T_("source") = 627^(@)C = 627 + 273 = 900K` `T_("sink") = 27^(@)C = 27 + 273 = 300K` Efficiency `(eta)= 1 - (T_("sink"))/(T_("source")) = 1-(300)/(900) = 1- (1)/(3)` `(eta) = (2)/(3) = ("Output")/("Input") = ("Work")/(Heat Input")` `implies (2)/(3) xx "Heat Input" = "Work"` `implies (2)/(3) xx 3xx10^(6) xx 4.2 = "Work"` `implies "Work" = 8.4 xx 10^(6)J` |
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