First Law of Thermodynamics

In adiabatic process

• temperature remain constant

• volume remain constant

• heat content remain constant

• pressure remain constant

Which law of thermodynamics is used to understand concept of energy conservation ?

• Zeroth law

• First law

• Second law

• Third law

In Carnot's cycle ,the last step is

• Isothermal expansion

• Isothermal compression

• adiabatic expansion

• adiabatic compression

In cyclic process ,the system is restored to the initial state at the end of the cycle .

• true

• false

The P-V diagram of isobaric process is a

• straight line parallel to pressure axis

• parabolic about pressure axis

• straight line passing through origin

• straight line parallel to volume axis

If the temperature of sink and source is same ,then the efficiency of Carnot's engine is

• 1

• 0

• -1

• None of these

A Carnot engine whose heat sink is at 27 degree Celsius utilizes 40% of heat absorbed into useful work.How much should be the change in temperature of source that its efficiency becomes 50%?

• 150 K

• 200 K

• 100 K

• 250

If the temperature of source is increased ,the efficiency of a Carnot engine

• increases

• decreases

• remain constant

• first increases and then remain constant

A gas performs maximum work when it expands

• isothermally

• adiabatically

• isobarically

• isochorically

A reversible and irreversible heat engines are working between same two temperatures .The efficiency of

• both is same

• reversible is greater

• irreversible is greater

• none of these