- Exam
- JEE Advanced
- Year
- 2023
- Paper
- Paper 2
- Subject
- Physics
- Chapter
- Units and Dimensions
JEE Advanced 2023 · Paper 2 · Physics · Units and Dimensions
Young’s modulus of elasticity Y is expressed in terms of...
Options
- A
- B
- C
- D
Correct answer
A.
Step-by-step solution
Dimensions of Young's modulus:
Dimensions of velocity of light: \left[{M}^{0}{L}^{1}{T}^{– 1}\right]
Dimensions of Gravitational constant: \left[{M}^{– 1}{L}^{3}{T}^{– 2}\right]
= {\left[{M}^{0}{L}^{1}{T}^{– 1}\right]}^{\alpha}{\left[{M}^{1}{L}^{2}{T}^{– 1}\right]}^{\beta}{\left[{M}^{– 1}{L}^{3}{T}^{– 2}\right]}^{\gamma}
Comparing exponent of the M, L & T both sides, we get1 = \beta - \gamma ⇒ \beta = 1 + \gamma . . . \left(1\right)- 1 = \alpha + 2\beta + 3\gamma . . . \left(2\right)
and
From equation(1) and (2), we get- 1 = \alpha + 2\left(1 + \gamma\right) + 3\gamma ⇒ \alpha + 5\gamma = - 3 . . . \left(4\right)
From equation(1)- 2 = - \alpha - \left(1 + \gamma\right) - 2\gamma ⇒ \alpha + 3\gamma = 1 . . . \left(5\right)
From equation(4)\alpha = 7, \gamma = – 2\beta = 1 + \gamma = - 1.