When the temperature of a copper coin is raised by `80^@C`, its diameter increases by `0.2%`.

Options

A. percentage rise in the area of a face is 0.4%
B. percentage rise in the thickness is 0.4%
C. percentage rise in the volume is 0.6%
D. coefficient of linear expansion of copper is` 0.25 xx 10^(-4) //^@ C `

Answer

A, C, D

Explanation

here `(Delta A )/(A ) xx 100 = 2 ((Delta l )/(l )) xx 100`
percentage increase in area `= 2 xx 0.2 = 0.4 % `
Now ` (Delta V)/(V ) xx 100 = 3 xx 0.2 = 0.6 % `
since `Delta l = l alpha Delta T `
` (Delta l )/( V ) xx 100 = alpha Delta T xx 100 = 0.2`
` therefore alpha = 0.25 xx 10^(-4) //^@ C `