Respuesta :
Answer:
The change in the area of the circle is [tex]8.88\times10^{-7}\ m^2[/tex]
Explanation:
Given that,
Radius = 0.250 cm
Temperature = 20.0°C
Final temperature =800.0°C
Coefficient of linear thermal expansion for lead[tex]\alpha =29.0\times10^{-6}\ /\°C [/tex]
We calculate the change in temperature,
[tex]\Delta T=800.0-20.0=780^{\circ}[/tex]
Now, We calculate the area of the disc
[tex]A = \pi r^2[/tex]
Put the value into the formula
[tex]A=3.14\times(2.5\times10^{-3})^2[/tex]
[tex]A =1.9625\times10^{-5}\ m^2[/tex]
We need to calculate the areal expansion
[tex]\Delta A=2\alpha\times A\times\Delta T[/tex]
[tex]\Delta A=2\times29.0\times10^{-6}\times1.9625\times10^{-5}\times780[/tex]
[tex]\Delta A=8.88\times10^{-7}\ m^2[/tex]
Hence, The change in the area of the circle is [tex]8.88\times10^{-7}\ m^2[/tex]
