NEET Practice Questions (MCQs) with Answers & Solutions

The Kelvin-Planck statement explicitly says: 'No process is possible whose sole result is the absorption of heat from a reservoir and the complete conversion of the heat into work.' This implies that a heat engine can never have an efficiency of unity (100%).

The Clausius statement explicitly states: 'No process is possible whose sole result is the transfer of heat from a colder object to a hotter object.' This means that heat naturally flows from hot to cold, and to reverse this flow (as in a refrigerator), external work must be done.

The NCERT text states: 'It can be proved that the two statements above are completely equivalent.'

The NCERT text explicitly states: 'In simple terms, it says that efficiency of a heat engine can never be unity. For a refrigerator, the Second Law says that the co-efficient of performance can never be infinite.'

The NCERT summary states: 'Spontaneous processes of nature are irreversible. The idealised reversible process is a quasi-static process with no dissipative factors such as friction, viscosity, etc.' Therefore, spontaneous processes are typically irreversible and associated with dissipative factors.

Option 4 is a statement of the First Law of Thermodynamics (conservation of energy). Options 1, 2, and 3 are direct consequences or statements of the Second Law.

As explained in the NCERT text, such a process, while conserving energy (First Law), is never observed and is forbidden by the Second Law of Thermodynamics because it implies a spontaneous transfer of internal energy from a colder object (table) to provide ordered mechanical work (book jumping).

The NCERT text states: 'Put simply, the Second Law implies that no heat engine can have efficiency $\eta$ equal to 1 or no refrigerator can have co-efficient of performance $\alpha$ equal to infinity.' A 'perfect' engine/refrigerator would achieve these impossible limits.

The NCERT text mentions that 'Spontaneous processes of nature are irreversible.' Combustion is a spontaneous and irreversible chemical process. Ideal gas expansion (if quasi-static) and phase changes at equilibrium are often considered idealized reversible processes, and heat transfer in a vacuum itself doesn't make the entire system reversal without other actions.

According to the NCERT text, Annelids exhibit organ-system level of body organisation and bilateral symmetry. They are triploblastic, metamerically segmented and coelomate animals.