Single correct · +4 / −1
The SI unit of Young's modulus is:
- (a) N/m
- (b) N/m²
- (c) N·m
- (d) kg/m²
Answer and solution
Answer (b) N/m²
Solution
Physics sir · 3 steps
Young's modulus is stress divided by strain, and strain has no unit, so Y carries the unit of stress.
- Definition. Young's modulus is the ratio of longitudinal stress to longitudinal strain.
Y = stress/strain = (F/A)/(Δ L/L)
- Unit of each part. Stress is force per area, so its unit is N m⁻². Strain is a length divided by a length, so it has no unit at all.
- So. Y has the same unit as stress: N/m², also called the pascal (Pa). That is option (b).
The idea to keep. Every elastic modulus (Young's, bulk, shear) is stress over a unitless strain, so all of them share the unit of pressure, N/m² or Pa.
Answer from the NTA final answer key. Solution by PrepWiser.