StreakPeaked· Practice

ExamsJEE AdvancedPhysics

If speed (V), acceleration (A), and force (F) are taken as fundamental quantities, what is the dimensional formula for Young's modulus in terms of these quantities?

  1. V^(-2) A² F²
  2. V^(-4) A² F
  3. V^(-4) A^(-2) F
  4. V^(-2) A² F^(-2)

Correct answer: V^(-4) A² F

Solution

Young's modulus Y has dimensions [M L⁻¹ T⁻²] (same as pressure). We need to express this using V=[LT⁻¹], A=[LT⁻²], F=[MLT⁻²]. From A/V = T⁻¹, so T = V/A (dimension-wise: T ~ V A⁻¹). L = V*T = V² A⁻¹. M = F/(A*L) = F/(A * V² A⁻¹) = F A⁰ V⁻²... let me redo: M = F T² L⁻¹ = F (V/A)² (V²/A)⁻¹ = F V² A⁻² * A V⁻² = F A⁻¹. Now [Y] = M L⁻¹ T⁻² = (F A⁻¹)(V² A⁻¹)⁻¹ (V A⁻¹)⁻² = F A⁻¹ * A V⁻² * A² V⁻² = F A² V⁻⁴.

Related JEE Advanced Physics questions

⚔️ Practice JEE Advanced Physics free + battle 1v1 →