Which one of the following
is possible according to the second law of thermodynamics?
ऊष्मागतिकी के दूसरे नियम के अनुसार निम्नलिखित में से कौन सा संभव है?
A perpetual frictionless pendulum
Spontaneous flow of heat from a cold to a hot
body
Spontaneous compression of a gas without
external work
100% conversion of a
quantity of heat into work
A perpetual frictionless pendulum
A perpetual frictionless pendulum is a
reversible process where net heat and network exchange between the system and
the surroundings is zero for the combined (original and reverse) process. It
does not violate second law of thermodynamics.
Hence, the correct option is (A).
&Key Points:-
According
to second law of thermodynamics:
● Heat
cannot spontaneously flow from a colder to a hotter reservoir but only with the
expenditure of mechanical energy.
● Spontaneous
compression of a gas without external work is not possible.
● Heat
carries entropy, work carries none. Hence the complete conversion of heat to
work would require the destruction of entropy. (In all processes, entropy
either stays the same or increases).
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