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Average atomic mass of an element is the sum of the masses of its isotopes each multiplied by its natural abundance
Answer:
(a) The coefficient of performance of an irreversible refrigeration cycle is always less than the coefficient of performance of a reversible refrigeration cycle when both exchange energy by heat transfer with the same two reservoirs.
Explanation:
According to the Kelvin–Planck statement of the second law of thermodynamics ,it is not possible to construct a device which operates in cycle and does not produce effect on the environment than the production of work.
We know that
Coefficient of performance is the ratio of desired effect to the work input in a cycle.
Given all option is correct but most appropriate option is a.
So the option a is correct
(a) The coefficient of performance of an irreversible refrigeration cycle is always less than the coefficient of performance of a reversible refrigeration cycle when both exchange energy by heat transfer with the same two reservoirs.
Answer: C
Explanation:
Some poly nuclear aromatic hydrocarbons are not carcinogenic in themselves. However, when these are made to interact with living cells, enzymes in the cells could convert the polynuclear aromatic hydrocarbon into a carcinogenic material such as benzo-[a]-pyrene. This can now interact adversely with the deoxyribonucleic acid of living cells leading to genetic mutation, that is, irreversible changes in the genes of organisms.
