Practice question

Given: A steel rod of radius 0.005 m and length 1 m is compressed by a force producing a stress of 2 × 10 ⁷ N/m ² . If the Young's modulus of steel is 2 × 10 ¹¹ N/m ², what is the strain? These values define the system as per NCERT data. Formula: Young's modulus: Y = Stress / Strain. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Strain: Strain = Stress / Y = (2 × 10 ⁷ ) / (2 × 10 ¹¹ ) = 1 × 10 ⁻⁴ . Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.