Physical World Units and Measurements - Result Question 30

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32. According to Newton, the viscous force acting between liquid layers of area $A$ and velocity gradient $\Delta V / \Delta Z$ is given by $F=-\eta A \frac{\Delta V}{\Delta Z}$ where $\eta$ is constant called coefficient of viscosity. The dimensional formula of $\eta$ is

======= ####32. According to Newton, the viscous force acting between liquid layers of area $A$ and velocity gradient $\Delta V / \Delta Z$ is given by $F=-\eta A \frac{\Delta V}{\Delta Z}$ where $\eta$ is constant called coefficient of viscosity. The dimensional formula of $\eta$ is

3e0f7ab6f6a50373c3f2dbda6ca2533482a77bed:content/english/neet-pyq-chapterwise/physics/physical-world-units-and-measurements/physical-world-units-and-measurements—result-question-30.md (a) $ML^{-2} T^{-2}$

(c) $ML^{2} T^{-2}$

(b) $M^{0} L^{0} T^{0}$

(d) $ML^{-1} T^{-1}$

[1990]

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Answer:

Correct Answer: 32. (d)

Solution:

(d) $F=-\eta A \frac{\Delta V}{\Delta Z}$

$\Rightarrow \eta=(-1) \frac{F \Delta Z}{A \Delta V}$

So dimensional formula of $\eta$

$\Rightarrow \frac{[MLT^{-2}][L]}{[L^{2}][LT^{-1}]}$

$\Rightarrow[ML^{-1} T^{-1}]$