Which of the following equations does not correctly represent the first law of thermodynamcis?

Options

A. isothermal process : `q=-w`
B. cyclic process : `q=-w`
C. isocharic process : `DeltaE=q`
D. adiabatic process : `DeltaE=-w`

Answer

D

Explanation

According to `1st` law of thermodynamics,
`DeltaE=q+w`
For isothermal process, `DeltaE=0`. Hence `q=-w`
For cyclic process, `DeltaE=0`. Hence `q=-w`
For isobaric process, `DeltaV=0`
Hence `DeltaE=q(w=PDeltaV=0)`
For adiabatic process, `q=0`. Hence, `DeltaE=w`
For expansion in vacuum, `w=0` Hence
`DeltaE=q`
`:. (D)` is incorrect