JEE Main2014PhysicsThermal Properties of MatterActual
The pressure that has to be applied to the ends of a steel wire of length 10 cm to keep its length constant when its temperature is raised by 100 ° C is : (For steel, Young's modulus is 2 × 10 11 N m - 2 and coefficient of thermal expansion is 1 . 1 × 10 - 5 K - 1 )
Options
- A2 .2 × 10 8   Pa
- B2 .2 × 10 9   Pa
- C2 .2 × 10 7   Pa
- D2 .2 × 10 6   Pa
Correct answer
A. 2 .2 × 10 8   Pa
Step-by-step solution
Young's modulus, Y = F A L Δ L ∴ F A = Y Δ L L = Y α Δ T ∴ P = 2 ×​ 10 11 × 1 .1 × 10 - 5 × 10 2 ∴   P = 2 . 2 × 10 8   Pa