A steel tape Im long is correctly calibrated for a temperature of `27.0 ^(@) C`. The length of a steel rod measured by this tape is found to be `63.0` cm on a hot day when the temperature is `45.0^(@) C` .What is the actual length of the steel rod on that day? What is the length of the same steel rod on a day when the temperature is `27.0^(@) C` ? Coefficient of linear expansion of steel `= 1.20 xx 10^(-5) K^(-1)`.

Explanation

Actual length of the rod at `45.0^(@) C = (63.0 + 0.0136) cm = 63.0136 cm`. (However, we should say that change in length up to three significant figures is` 0.0136` cm, but the total length is` 63.0 `cm, up to three significant places Length of the same rod at `27.0^(@) C = 63.0 `cm.