Question

A metre scale made of a metal reads accurately at 25 °C. Suppose in an experiment an accuracy of 0.12 mm in 1 m is required, the range of temperature in which the experiment can be performed with this metre scale is ______.(coefficient of linear expansion of the metal is `20 xx 10^-6 / (°"C")`

पर्याय

• 19 °C to 31 °C

• 25 °C to 32 °C

• 18 °C to 25 ° C 

• 18 °C to 32 °C

Answer 1

A metre scale made of a metal reads accurately at 25 °C. Suppose in an experiment an accuracy of 0.12 mm in 1 m is required, the range of temperature in which the experiment can be performed with this metre scale is 19 °C to 31 °C.

Explanation:

`l_2 - l_1 = l_1  alpha  ("T"_2 - "T"_1)`

` "T"_2 - "T"_1 = (12 xx 10^-5)/(1 xx 20 xx 10^-6) ≈ 4.7 "A"`

Hence, range of temperature is (25 -6)°C to (25 + 6)°C

i.e., 19 °C to 31 °C