Question

Which one of the following equations does not correctly respresents the first law of thermodynamics for the given process?
A. Isothermal process: `q= -w`
B. Cyclic process: q= -w
C. Adiabatic process: `Delta E=q`
D. Expansion of a gas into vaccum: `Delta E=q`

Answer 1

Correct Answer - C
Accoring to 1 st law of thermodynamics,
`Delta E=q+w`.
For isothermal process, `Delta E=0`. Hence, `q= -w`
For cyclic process, `Delta E=0` Hence,
For expansion into vaccum, `w=0`. Hence `Delta E=q`.