Easy MCQ +4 / -1 PYQ · JEE Mains 2021

Each side of a box made of metal sheet in cubic shape is 'a' at room temperature 'T', the coefficient of linear expansion of the metal sheet is '$\alpha$'. The metal sheet is heated uniformly, by a small temperature $\Delta$T, so that its new temperature is T + $\Delta$T. Calculate the increase in the volume of the metal box.

  1. A 3a<sup>3</sup>$\alpha$$\Delta$T Correct answer
  2. B 4$\pi$a<sup>3</sup>$\alpha$$\Delta$T
  3. C ${{4 \over 3}}$$\pi$a<sup>3</sup>$\alpha$$\Delta$T
  4. D 4a<sup>3</sup>$\alpha$$\Delta$T

Solution

We know that, $\gamma = 3\alpha$ .... (i)<br/><br/>where, $\alpha$ is the coefficient of linear expansion and $\gamma$ is the coefficient of volume expansion. <br/><br/>We know that,<br/><br/>${{\Delta V} \over V} = \gamma \Delta T$<br/><br/>$\Rightarrow {{\Delta V} \over V} = 3\alpha \Delta T$ [from Eq. (i)]<br/><br/>$\Delta V = 3{a^3}\alpha \Delta T$ [ $\because$ volume of cube = a<sup>3</sup> ]

About this question

Subject: Physics · Chapter: Thermodynamics · Topic: Zeroth and First Law

This question is part of PrepWiser's free JEE Main question bank. 271 more solved questions on Thermodynamics 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 →