Join the Most Relevant JEE Main 2025 Test Series & get 99+ percentile! Join Now
Search any question & find its solution
Question: Answered & Verified by Expert
In which of the following pairs, the two physical quantities have different dimensions?
PhysicsUnits and DimensionsWBJEEWBJEE 2014
Options:
  • A Planck's constant and angular momentum
  • B impulse and linear momentum
  • C Moment of inertia and moment of a force
  • D Energy and torque
Solution:
2027 Upvotes Verified Answer
The correct answer is: Moment of inertia and moment of a force
(a) Planck's constant = Energy
$=\left[\mathrm{ML}^{2} \mathrm{T}^{-1}\right]$
Angular momentum = Moment of inertia Angular velocity
$=\left[\mathrm{ML}^{2}\right] \times\left[\mathrm{T}^{-1}\right)=\left[\mathrm{ML}^{2} \mathrm{T}^{-1}\right]$
(b) Impulse = Force x Time
$=\left[\mathrm{MLT}^{-2}\right] \mathrm{IT}=\left[\mathrm{MLT}^{-1}\right]$
and linear momentum = Mass $\times$ Velocity
$=\left[\mathrm{M}\left[\mathrm{LT}^{-1}\right]=\left[\mathrm{MLT}^{-1}\right)\right.$
(c) Moment of inertia = Mass $\times(\text { Distance })^{2}$
$=\left[M L^{2}\right]$
and moment of force = Force x Distance
$=\left[\mathrm{MLT}^{-2}\right] \mathrm{U}=\left[\mathrm{M}^{2} \mathrm{T}^{-2}\right]$
(d) Energy $=\left[\mathrm{ML}^{2} \mathrm{T}^{-2} \mathrm{l}\right.$ and torque $=\left[\mathrm{ML}^{2} \mathrm{T}^{-2} 1\right.$
So, (c) option has different dimensions.

Looking for more such questions to practice?

Download the MARKS App - The ultimate prep app for IIT JEE & NEET with chapter-wise PYQs, revision notes, formula sheets, custom tests & much more.