Question

A brass scale is graduated at `10^@C`. What is the true length of a zinc rod which measures 60.00 cm on this scale at `30^@C`?
Coefficient of linear expansion of brass`=18xx10^-6K^-1`.

Answer 1

Since the scale is graduated at `10^@C`,
1 cm of the scale at `10^@C`
= exactly 1 cm
`:. 1` cm of the scale at `30^@C`
= exactly `(1+18xx10^(-6) xx20)` cm
`:.` 60 cm of the scale at `30^@C`
= exactly `60.00(1+36xx10^-5)`
`=60.02cm`.