Question

a metal sheet is of 4m*3m size what is the increase in its surface area when heated through 80°C？given the coefficient of superficial expansion of the metal is 2.4*20^-5/°C​

Answer 1

Answer:

Formula for linear expansion of a metal is;

L = L initial ( 1 + α (t2 – t1))

Linitial is the initial length at temperature t1, t2 is the final temperature and α is the cofficent of thermal expansion expansion.

We now apply this formula for length 3 and 4 meters.  

L = 3 (1 + α (80))  

Here we are given that α = 2.4*20^-5 =  0.00000075  

L = 3 (1 + 0.00000075 (80))  

L’ = 3.00018

Similarly for dimension 4 m  

L’ = 4 (1 + 0.00000075 (80))  

L’ = 4.00024

Now original area was;  

A = 3 x 4 = 12  m^2

After expansion, area will be;  

A’ = 4.00024 x 3.00018  

A’ = 12.00144 m^2

 

Net increase in area will be;  

= A’ – A  

=  0.00144 m^2

Hope this helps you

Thank you :)