Question

A brass meter bar is correct at 15 degree Celsius. The length of rod as measured by it at 30 degree Celsius is 40cm. The true length of the rod at 30 degree Celsius is

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