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Q. Match List I with List II
LIST I LIST II
A Young's Modulus (Y) 1 $\left[ M L ^{-1} T ^{-1}\right]$
B Co-efficient of Viscosity $(\eta)$ 2 $\left[ M L ^2 T ^{-1}\right]$
C Planck's Constant (h) 3 $\left[ M L ^{-1} T ^{-2}\right]$
D Work Function $(\phi)$ 4 $\left[ M L ^{-2} T ^{-2}\right]$
Choose the correct answer from the options given below:

JEE MainJEE Main 2023Physical World, Units and Measurements

Solution:

$Y =\frac{\text { Stress }}{\text { Strain }}=\frac{ F / A }{\Delta \ell / \ell}=\frac{\left[ MLT ^{-2}\right]}{\left[ L ^2\right]}=\left[ ML ^{-1} T ^{-2}\right] $
$ F =6 \pi \eta rv \Rightarrow \eta=\frac{ F }{6 \pi rv } $
$ {[\eta]=\frac{\left[ MLT ^{-2}\right]}{[ L ]\left[ LT ^{-1}\right]}=\left[ ML ^{-1} T ^{-1}\right]} $
$ E = hv \Rightarrow h =\frac{ E }{v}=\frac{\left[ ML ^2 T ^{-2}\right]}{\left[ T ^{-1}\right]}=\left[ ML ^2 T ^{-1}\right]$
Work function has same dimension as that of energy, so $[\phi]=\left[ ML ^2 T ^{-2}\right]$