Q. If $\mathrm{\Delta}Q$ and $\mathrm{\Delta}W$ represent the heat supplied to the system and the work done on the system respectively, then the first law of thermodynamics can be written as Where $\mathrm{\Delta}U$ is the internal energy
A) $\mathrm{\Delta}Q = \mathrm{\Delta}U + \mathrm{\Delta}W$
B) $\mathrm{\Delta}Q = \mathrm{\Delta}U - \mathrm{\Delta}W$
C) $\mathrm{\Delta}Q = \mathrm{\Delta}W - \mathrm{\Delta}U$
D) $\mathrm{\Delta}Q = - \mathrm{\Delta}W - \mathrm{\Delta}U$
Explanation
(b) From FLOT $\mathrm{\Delta}Q = \mathrm{\Delta}U + \mathrm{\Delta}W$
$\because$ Heat supplied to the system so $\mathrm{\Delta}Q \rightarrow$ Positive
and work is done on the system so $\mathrm{\Delta}W \rightarrow$ Negative
Hence $+ \mathrm{\Delta}Q = \mathrm{\Delta}U - \mathrm{\Delta}W$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.