एक गोलाकार पिंड जिसकी त्रिज्या \(r\) और घनत्व \(\sigma\) है, एक श्यान द्रव से होकर स्वतंत्र रूप से गिरता है जिसका घनत्व \(\rho\) और श्यानता \(\eta\) है और सीमांत वेग \(v _0\) प्राप्त करता है। राशि \(\eta\) में अनुमानित अधिकतम त्रुटि है: ( \(\sigma, \rho\) और g (गुरुत्वीय त्वरण) से संबंधित त्रुटियों को अनदेखा करें)

A \(2 \frac{\Delta r }{ r }-\frac{\Delta v _0}{ v _0}\)
B \(\frac{2 \Delta r }{ r }+\frac{\Delta v _0}{ v _0}\)
C \(2\left[\frac{\Delta r }{ r }+\frac{\Delta v _0}{ v _0}\right]\)
D \(2\left[\frac{\Delta r }{ r }-\frac{\Delta v _0}{ v _0}\right]\)

Verified Solution

Answer & Solution

Correct Answer

(B) \(\frac{2 \Delta r }{ r }+\frac{\Delta v _0}{ v _0}\)

Step-by-step Solution

Detailed explanation

\(v _0=\frac{2}{9} \frac{ r ^2 g}{ n }\left(\rho_{ B }-\rho_{ L }\right)\) \(n =\frac{2}{9} \frac{ r ^2 g}{ v _0}\left(\rho_{ B }-\rho_{ L }\right)\) \(\frac{\Delta n }{ Il }=\frac{2 \Delta r }{ r }+\frac{\Delta v _0}{ v _0}\)

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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