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JEE Main 202431 JanuaryMorning Shift
Exam
JEE Main
Year
2024
Date
31 January
Shift
Morning Shift
Subject
Physics
Chapter
Units and Dimensions

JEE Main 2024 · 31 January · Morning Shift · Physics · Units and Dimensions

A force is represented by F = a x ^ 2 + bt(1)/(2) , where x =...

A force is represented by F=ax2+bt12F = a{x}^{2} + bt\dfrac{1}{2}, where x=x = distance and t=t = time. The dimensions of b2a\dfrac{{b}^{2}}{a} are :

Options

  1. A[ML3T–3][ M{L}^{3}T{}^{– 3} ]
  2. B[MLT–2][ ML{T}^{– 2} ]
  3. C[ML–1T–1][ M{L}^{– 1}{T}^{– 1} ]
  4. D[ML2T–3][ M{L}^{2}{T}^{– 3} ]

Correct answer

A. [ML3T–3][ M{L}^{3}T{}^{– 3} ]

Step-by-step solution

Given: F=ax2+bt12F = a{x}^{2} + bt\dfrac{1}{2}

Dimension of \left[a\right] = \dfrac{\left[F\right]}{\left[{x}^{2}\right]} = \dfrac{\left[ML{T}^{- 2}\right]}{\left[{L}^{2}\right]} = \left[{M}^{1}{L}^{- 1}{T}^{- 2}\right]</p><p>Dimensionof [b]=[F][t12]=[MLT−2][T12]=[M1L1T−52]</p><p>Dimension of \left[b\right] = \dfrac{\left[F\right]}{\left[{t}^{\dfrac{1}{2}}\right]} = \dfrac{\left[ML{T}^{- 2}\right]}{\left[{T}^{\dfrac{1}{2}}\right]} = \left[{M}^{1}{L}^{1}{T}^{- \dfrac{5}{2}}\right]

Required value, \left[\dfrac{{b}^{2}}{a}\right] = \dfrac{\left[{M}^{2}{L}^{2}{T}^{- 5}\right]}{\left[{M}^{1}{L}^{- 1}{T}^{- 2}\right]} = \left[{M}^{1}{L}^{3}{T}^{- 3}\right]$

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