Question

A brass rod at 30c is observed to be 1m long when measured by steel scale which is correct at 0c. Find length of rod at 0c. Given alpha=0.00012 per c and alpha for brass=0.000019 per c

Answer 1

As steel scale is correct at 0℃.  

Actual length measured by steel scale at 30℃.

L = 100 ( 1 + t × α )

L = 100 (1.00036)cm

L = 100.036 c m

Brass rod has length 100.036cm at 30℃ let's assume length L' is length at 0℃

so -

100.036 = L ′( 1 + t × α )

100.036 = L ′ (1.00057)

L' = 99.979 c m