Practice question
Question
An aluminium wire of length 2.5m and cross-sectional area 1.5×10−6m2 is stretched by a force of 150N. If the Young's modulus of aluminium is 7×1010N/m2, what is the stress?
Explanation
Stress: Stress = FA = 1501.5×10−6 = 1×108N/m2. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 1×108N/m2. This satisfies dimensional consistency and physical conditions given, so option A is scientifically correct.