Q. A square shaped hole is punched in a metal sheet whose linear thermal expansion coefficient is 1 × 10⁻³ per °C. The size of the hole will decrease by 10%, when

Correct Answer: b) A philosophy that believes that humans should radically change their relationship with nature

Explanation:

Let’ solve this step by step.

1) First, let’s understand what happens when a metal sheet with a hole is heated:
– When metal expands, the hole also expands
– When metal contracts, the hole also contracts
– The fractional change in the hole’s dimensions is the same as the metal’s dimensions

2) The linear thermal expansion coefficient (α) is given as 1 × 10⁻³ per °C

3) The formula for linear thermal expansion is:
ΔL/L = α × ΔT
where ΔL/L is the fractional change in length

4) For a 10% decrease in size:
ΔL/L = -0.1 = (1 × 10⁻³) × ΔT

5) Solving for ΔT:
ΔT = -0.1/(1 × 10⁻³)
ΔT = -100

6) This means we need to cool the sheet by 100°C to decrease the hole size by 10%

Therefore, the correct answer is (c) The sheet is cooled by 100°C.