An iron bar of length I and having a cross-section area A is heated from `0^(@)` to `100^(@)C`. If this bar is so held that it is not permitted to expand or bend, the force that is developed, is

Options

A. Inversely rhoortional to the cross-sectional area of the bar
B. Independent of the length of the bar
C. Inversely rhoortional to the length of the bar
D. Directly rhoortional to the length of the bar

Answer

B

Explanation

Since, `Y = (FL)/(A delta l)`
`rArr F = (YA Delta l)/(L)`
Since, `alpha = (Delta l)/(L Delta T) = 100 alpha = (Delta l)/(L)`
`therefore F = YA xx alpha xx 100 = YA xx 100 alpha`
Force is independent of length L.