Medium MCQ +4 / -1 PYQ · JEE Mains 2022

A water drop of diameter 2 cm is broken into 64 equal droplets. The surface tension of water is 0.075 N/m. In this process the gain in surface energy will be :

  1. A 2.8 $\times$ 10<sup>$-$4</sup> J Correct answer
  2. B 1.5 $\times$ 10<sup>$-$3</sup> J
  3. C 1.9 $\times$ 10<sup>$-$4</sup> J
  4. D 9.4 $\times$ 10<sup>$-$5</sup> J

Solution

<p>$r' = {r \over 4}$</p> <p>$\Rightarrow \Delta E = T(\Delta S)$</p> <p>$= T \times 4\pi (nr{'^2} - {r^2}),\,n = 64$</p> <p>$= T \times 4\pi \times (4 - 1){r^2}$</p> <p>$\Rightarrow \Delta E = 0.075 \times 4 \times 3.142(3) \times {10^{ - 4}}\,$ J</p> <p>$= 2.8 \times {10^{ - 4}}$ J</p>

About this question

Subject: Physics · Chapter: Properties of Solids and Liquids · Topic: Elasticity

This question is part of PrepWiser's free JEE Main question bank. 183 more solved questions on Properties of Solids and Liquids are available — start with the harder ones if your accuracy is >70%.

Drill 25 more like these. Every day. Free.

PrepWiser turns these solved questions into a daily practice loop. Chapter-wise drills, full mocks, AI doubt chat. No auto-renew.

Start free →