**Question:**

**Dimensional formula for thermal conductivity is (here $K$ denotes the temperature:**

MLT $^{-2} \mathrm{~K}$

$\mathrm{MLT}^{-2} \mathrm{~K}^{-2}$

$\mathrm{MLT}^{-3} \mathrm{~K}$

$\mathrm{MLT}^{-3} \mathrm{~K}^{-1}$

Question of from chapter.

JEE Main Previous Year 2020

Correct Option: 4

**Solution:**

\begin{aligned}

&\text { From formula, } \frac{d Q}{d t}=k A \frac{d T}{d x} \\

&\Rightarrow k=\frac{\left(\frac{d Q}{d t}\right)}{A\left(\frac{d T}{d x}\right)} \\

&{[k]=\frac{\left[\mathrm{ML}^{2} \mathrm{~T}^{-3}\right]}{\left[\mathrm{L}^{2}\right]\left[\mathrm{KL}^{-1}\right]}=\left[\mathrm{MLT}^{-3} \mathrm{~K}^{-1}\right]}

\end{aligned}

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