An iron bar of length l and cross-section A is heated from 0°C to 100°C. If the rod is so held that it is not permitted to expand or bend, the force developed in it is :

An iron bar of length l and cross-section A is heated from 0°C to 100

1.	An iron bar of length l and cross-section A is heated from 0°C to 100°C. If the rod is so held that it is not permitted to expand or bend, the force developed in it is :
Answer» directly PROPORTIONAL to length inversely proportional to length independent of length inversely proportional to area of cross-section Solution :Change in length `Deltal=alDeltaT` Stress = `F/A` and STRAIN= `(Deltal)/l` Now Y =`F/Axxl/(Deltal)=F/Axxl/(alphalDeltaT)` or` ~F=YalphaADeltaT` Clearly F does not depend upon length. Hence the correct CHOICE is (C).

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An iron bar of length l and cross-section A is heated from 0°C to 100°C. If the rod is so held that it is not permitted to expand or bend, the force developed in it is :

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