Concepts Of Physics MCQ Edition [Volume 1]PhysicsIntroduction to Physics
Determine if the following equation is dimensionally correct: V = P r^4 t 8 l where h = height, S = surface tension, = density, P = pressure, V = volume, = coefficient of viscosity, = frequency and I = moment of inertia.
Options
- AThe equation is dimensionally incorrect, as the right side has dimensions of [M L^2 T⁻²] .
- BThe equation is dimensionally incorrect, as the right side has dimensions of [L^2] .
- CThe equation is dimensionally correct.
- DThe equation is dimensionally incorrect, as the right side has dimensions of [L^3 T⁻¹] .
Correct answer
C. The equation is dimensionally correct.
Step-by-step solution
The dimensions of the terms are evaluated as follows: [V] = [L^3] [P] = [M L⁻¹ T⁻²] [r] = [L] [t] = [T] [ ] = [M L⁻¹ T⁻¹] [l] = [L] Substituting these dimensions into the right hand side of the given equation: [M L⁻¹ T⁻²] [L^4] [T] [M L⁻¹ T⁻¹] [L] = [M L^3 T⁻¹] [M L^0 T⁻¹] = [L^3] Since the dimensions of the left hand side and right hand side are equal, the equation is dimensionally correct.