On a fairly cool rainy day when the temperature is 20oC, the length of a steel railroad track is 20m. What will be its length on a hot a dry day when the temperature is 40oC?
[coefficient of linear expansion of steel = 11 x 10-6K-1]
[coefficient of linear expansion of steel = 11 x 10-6K-1]
-
A.
20.013m -
B.
20.009m -
C.
20.004m -
D.
20.002m
Correct Answer: Option C
Explanation
The increase in length of the steel rail is given by
= α 10
= 11 x 10-6 x 20 x (40 -20)
= 11 x 10-6 x 20 x 20
= 4.4 x 10-3
∴ Final length will be original length plus increase in length
= 20 + 4.4 x 10-3
= 20 + 0.0044
= 20.0044m