Question

. At 20℃ the length of each side of a platinum cube is 25cm. Find the increase in the surface area of the cube when the temperature of the cube rises to 75℃

Answer 1

T₁= 20℃

T₂=75℃

∆T= 75-20

∆T= 55℃

Thermal expansion cofficient platinum = 0.000009 /℃

Area expansion cofficient =2 = 0.000018 /℃

Side of cube a=25 cm = 0.25m

Surface area of cube A= 6×a²

A = 6×(0.25)² =0.375 m²

change in surface area ∆A= ×A×∆T

∆A= 0.000018× 0.375×55

∆A= 0.000371 m²

∆A= 3.71 cm²

Increase in surface area when temperature goes 20℃ to 75℃ will be 3.71 cm²

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