Time taken by a $$836$$ $$W$$ heater to heat one litre of water from $$10{}^ \circ C$$ to $$40{}^ \circ C$$ is

Which of the following statements is correct for any thermodynamic system ?

A carnot engine takes $$3 \times {10^6}$$ cal. of heat from a reservoir at $${627^ \circ }C,$$ and gives it to a sink at $${27^ \circ }C$$. The work done by the engine is

''Heat cannot by itself flow from a body at lower temperature to a body at higher temperature'' is a statement or consequence of :