Select all the correct statements aThe first law requires th

Select all the correct statements a)The first law requires that heat is transferred from a hot object to a cold object b)It is possible to design a machine that separates a mixture of oxygen and nitrogen into its components without the use of any external energy source c)The first law allows heat to be transfered from a cold object to a hot object d)In a power plant the heat out from the condenser can be reduced to zero so that the net power delivered by the plant is maximized.

Solution

A) false : because first law States that heat and work mutually transferable.i,e. Energy neither created nor destroyed.

B) false : no device can extract energy with out any external source. Eg : ppm 1.

C) false : no device can transfer heat from cold body to hot body with out any external work.

D) false : heat out should be max in condenser then only max plant efficiency occurs.