Young’s modulus of steel is 1.9 × 1011 N/m2. When expressed in CGS units of dynes/cm2, it will be equal to: a) 1.9 × 1010 b) 1.9 × 1011 c) 1.9 × 1012 d) 1.9 × 1013
Dyne and Newton, both are units of force. While Dyne is specified in C-G-S(Centimeter – Gram – Second) unit system, Newton is specified in modern SI unit system which gives the relationship Young’s Modulus between stress and strain. It is used to measure hardness of material. Here stress is force applied per unit area, strain is deformation happened on object. E=ϵ6=L0ΔLAF=AΔLFl0 Where, σ= Stress in Pascal ϵ= Strain or deformation F= Force A= Cross sectioned area ΔL= Change in Length Lo= Actual Length E= Young’s Modulus Here E=1.9×10N/M2 Let’s convert it into CGS unit system. =1.9×1011Newtons/meter2 =104cm21.9×1011×105 =1.9×1012dyne/cm2 E=1.9×1012dyne/cm2
