JEE Mains · Physics · STD 11 - Units,dimensions and measurement
- JEE Mains 2023
- Medium
- MCQ
Given below are two statements: one is labelled as Assertion \(A\) and the other is labelled as Reason \(R\) Assertion \(A\) : A spherical body of radius \((5 \pm 0.1)\) \(mm\) having a particular density is falling through a liquid of constant density. The percentage error in the calculation of its terminal velocity is \(4\,\%\). Reason \(R\) : The terminal velocity of the spherical body falling through the liquid is inversely proportional to its radius. In the light of the above statements, choose the correct answer from the options given below on :
Pick an option to check your answer.
Answer & Solution
Correct Answer
(D) \(A\) is true but \(R\) is false
Step-by-step Solution
Detailed explanation
Terminal velocity of a spherical body in liquid
\(\Rightarrow V _{ t } \propto r ^2\)
\(\Rightarrow \frac{\Delta V _{ t }}{ V _{ t }}=2 \cdot \frac{\Delta r }{ r }\)
\(\Rightarrow \frac{\Delta V _{ t }}{ V _{ t }} \times 100 \%=2 \frac{(0.1)}{5} \times 100=4\,\%\)
Also \(V_t \propto r^2\)
Reason \(R\) is false
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