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# The specific heat of a metal is 0.16, its approximate atomic weight would be

$\begin{array}{1 1}(a)\;32& (b)\;16 \\(c)\;64&(d)\;40\end{array}$

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A)
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• The modern form the Dulong–Petit law is : $\large cM = 3R$
• Dulong and Petit from their researches upon the elements concluded that the ultimate atoms of all elements possessed the same capacity for heat and they accordingly announced the law that :
" The specific heat of elementary substances is in their inverse ratio to their atomic weights."
• According to Dulong Petits law: Atomic weight × specific heat = 6.4
$\large\frac{6.4}{\text{specific heat}}$=Atomic weight
Atomic Weight = $\large\frac{6.4}{0.16}$
$\Rightarrow 40$
Henc (d) 40 is the correct answer.
Is question me 6.4 kaise samajh nahi ayi