\(r\) ત્રિજ્યા ધરાવતાં મોટી સંખ્યામાં પાણીનાં ટીપા સંયોજાઈને \(R\) ત્રિજ્યા ધરાવતું ટીપું સર્જે છે. જે પૃષ્ઠતાણ \(T\) અને ઉષ્માનો યાંત્રિક સમતુલ્યાંક \(J\) હોય તો પ્રતિ એકમ કદમાં ઉષ્મા ઉર્જામાં થતો વધારો ............ છે

A \(\frac{2 T }{ J }\left(\frac{1}{ r }-\frac{1}{ R }\right)\)
B \(\frac{2 T }{ rJ }\)
C \(\frac{3 T }{ rJ }\)
D \(\frac{3 T }{ J }\left(\frac{1}{ r }-\frac{1}{ R }\right)\)

Verified Solution

Answer & Solution

Correct Answer

(D) \(\frac{3 T }{ J }\left(\frac{1}{ r }-\frac{1}{ R }\right)\)

Step-by-step Solution

Detailed explanation

\(n \times \frac{4}{3} \pi r ^{3}=\frac{4}{3} \pi R ^{3}\) \(\therefore n ^{1 / 3} r = R\) \(\therefore\) Total change in surface energy \(=\left(n\left(4 \pi r^{2}\right)-4 \pi R^{2}\right) T\) \(\Rightarrow 4 \pi T \left( nr ^{2}- R ^{2}\right)\) \(\therefore\) Heat energy…

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.

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