A rectangular steel plate with dimensions of 60 cm × 25 cm is heated from 20°C to 150°C.What is its change in area? (Coefficient of linear expansion for steel is 11 × 10−⁶/°C. ) A) 0.82 cm² B) 1.1 cm² C) 4.3 cm² D) 6.6 cm²

Question

Quizplus · Accepted Answer

The change in area can be calculated using the formula:

ΔA = 2αAL

where α is the coefficient of linear expansion, A is the original area, L is the change in length, and the factor of 2 accounts for expansion in both dimensions.

The change in length can be calculated using the formula:

ΔL = αLΔT

where ΔT is the change in temperature.

Substituting the values given, we get:

ΔL = (11 × 10^-6/°C)(85 cm)(130°C) = 1.2825 cm

ΔA = 2(11 × 10^-6/°C)(60 cm × 25 cm)(1.2825 cm) = 4.332 cm^2 ≈ 4.3 cm^2

Therefore, the best choice is C.

A Rectangular Steel Plate with Dimensions of 60 Cm ×