NEET-XII-Physics
28: Heat Transfer
- #1The heat current is written as
∆Q∆t. Why don’t we write
dQdt?Ans : The amount of heat crossing through any cross-section of a slab in time `` ∆t`` is called heat current.
It is written as `` \frac{∆\,\mathrm{\,Q\,}}{∆t}`` and not as complete derivative `` \frac{d\,\mathrm{\,Q\,}}{dt}``. This is because the amount of heat crossing through any cross section is a function of many variables like temperature difference, area of cross-section, etc. So, we cannot write it as a complete derivative with respect to time.
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