A metre scale made of steel reads accurately at 20°C. In a sensitive experiment, distances up to 0.055 mm in 1 m are required. Find the range of temperature in which the experiment can be performed with this metre scale. Coefficient of linear expansion of steel = 11 × 10–6 °C–1.
Given:
Temperature at which meter scale gives accurate reading: T1=20° C
Change in Length required: Δ L=0.055mm = 0.055 x 10-3 m.
Original Length: L= 1 m.
Coefficient of linear expansion of steel: α = 11 x 10-6 ° C-1.
Formula used:
Now, we have the direct formula for change in length due to thermal expansion:
Where Δ L is the change in length.
Where Δ T is the change in temperature,
it can be T1+T2 OR T1-T2.
First let’s take T1-T2.
Now, let’s take T1+T2,
Hence, the range of the temperature within which this experiment can be performed with the given metre scale is 15° C to 25° C.