Question

- A brass scale is calibrated at 0°C . What is the correct length of a rod, which when measured with this scale at 30°C , is found to be 50 cm long ? ( alpha rass =1.8*10^-5 /°C)​

Answer 1

Answer:

As steel scale is correct at 0℃.

Actual length measured by steel scale at 30℃.

L=100(1+t×α)

L=100(1+12×10

−6

×30)

L=100(1.00036)cm

L=100.036cm

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+19×10

−6

×30)

100.036=L

′

(1.00057)

L

′

=99.979cm