Question

A metal sheet having size of $0)6\times 0)5$ $m^2$ is heated from 293 K to ${520}^{\circ }$C. The final area of the hot sheet is
($\alpha$ of metal $=2\times {10}^{-5}{/}^{\circ }$C)

• A. $0)306m^2$
• B. $0)0306m^2$
• C. $3)06m^2$
• D. $1)02m^2$

Answer 1

The correct option is A $0)306m^2$

In this case, $\beta =2\alpha =4$X${10}^{-5}$
$A_1$ $=$ $0.6\times 0.5$ $=$ $0.30$ sqmt
${293}^{\circ }$K $=$ ${20}^{\circ }$ C
So, $t_2-t_1=dt=520-20=500$
Putting all the values in
$A_2=A_1(1+\beta dt)$
$A_2=0.30(1+4$X${10}^{-5}$($500$))
We get $A_2=0.306$ sqmt