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MHT CET · Maths · Differential Equations

A differential equation for the temperature ' \(\mathrm{T}\) ' of a hot body as a function of time, when it is placed in a both which is held at a constant temperature of \(32^{\circ} \mathrm{F}\), is given by (where \(\mathrm{k}\) is a constant of proportionality)

  1. A \(\frac{\mathrm{dT}}{\mathrm{dt}}=\mathrm{kT}-32\)
  2. B \(\frac{\mathrm{dT}}{\mathrm{dt}}=\mathrm{kT}+32\)
  3. C \(\frac{\mathrm{dT}}{\mathrm{dt}}=\mathrm{k}(\mathrm{T}-32)\)
  4. D \(\frac{\mathrm{dT}}{\mathrm{dt}}=32 \mathrm{kT}\)
Verified Solution

Answer & Solution

Correct Answer

(C) \(\frac{\mathrm{dT}}{\mathrm{dt}}=\mathrm{k}(\mathrm{T}-32)\)

Step-by-step Solution

Detailed explanation

The temperature \(\mathrm{T}\) of the body will decrease with time. The body is kept in a bath of temperature \(32^{\circ} \mathrm{F}\).
\(
\begin{aligned}
& \therefore \frac{\mathrm{dT}}{\mathrm{dt}} \alpha-(\mathrm{T}-32) \\
& \Rightarrow \frac{\mathrm{dT}}{\mathrm{dt}}=-\mathrm{k}(\mathrm{T}-32)
\end{aligned}
\)