NEET 2015
- Exam
- NEET
- Year
- 2015
- Subject
- Physics
- Chapter
- Units and Dimensions
NEET 2015 · Physics · Units and Dimensions
If dimensions of critical velocity, v _ c of a liquid flowing...
If dimensions of critical velocity, of a liquid flowing through a tube are expressed as \left[{η}^{x}{ρ}^{y}r^{z}\right]η, ρ and rx\text{z}$ are given by
Options
- A
- B
- C
- D
Correct answer
D.
Step-by-step solution
Dimensions of velocity, coefficient of viscosity and density are,
\left[η\right] = \dfrac{\left[F\right]}{\left[A\dfrac{d v}{d x}\right]} = \dfrac{\left[{MLT}^{- 2}\right]}{\left[{L}^{2}\right]\left[{T}^{- 1}\right]} = \left[{ML}^{- 1}{T}^{- 1}\right]
Now, \left[v\right] = {\left[η\right]}^{x}{\left[ρ\right]}^{y}{\left[r\right]}^{z}⇒ \left[{LT}^{- 1}\right] = {\left[{ML}^{- 1}{T}^{- 1}\right]}^{x}{\left[{ML}^{- 3}\right]}^{y}{\left[L\right]}^{z}{M}^{0} = {M}^{\left(x + y\right)}⇒ y = - xTx = 1⇒ y =- x =- 1L1 = - x - 3y + z⇒ z = - 1