Question

Dimensions of Planck's constant are

• A. $[M{L}^2{T}^{-1}]$
• B. $[M{L}^2{T}^{-3}]$
• C. $[ML{T}^{-1}]$
• D. $[M{L}^3{T}^{-3}]$

Answer 1

Answer: (A)

Energy $[E]=$ Planck's constant $[A]\times$ Frequency $[v]$
$\Rightarrow E=hv$
$\Rightarrow [E]=[h][v]$
$\Rightarrow \left[M{L}^2{T}^{-2}\right]=[h]\left[\frac{1}{T}\right]$
$\Rightarrow [h]=\left[M{L}^2{T}^{-2}\right][T]$
$\therefore$ Dimension of $h=[h]=\left[M{L}^2{T}^{-1}\right]$