JEE Main2017PhysicsThermal Properties of MatterActual
A steel rail of length 5 m and area of cross section 40 cm 2 is prevented from expanding along its length while the temperature rises by 10 ° C . If coefficient of linear expansion and Young's modulus of steel are 1.2 × 10 - 5 K - 1 and 2 × 10 11 N m - 2 respectively, the force developed in the rail is approximately:
Options
- A2 × 10 7   N
- B2 × 10 9   N
- C3 × 10 - 5   N
- D1 × 10 5   N
Correct answer
D. 1 × 10 5   N
Step-by-step solution
F = Y A α Δ t ⇒ F = 2 × 10 11 × 40 × 10 - 4 × 1.2 × 10 - 5 × 10 ⇒ F = 9.6 × 10 4 ≈ 1 × 10 5   N .