question_answer

Two rods of lengths \[{{\ell }_{1}}\,\,and\,\,{{\ell }_{2}}\] are made of materials   whose   coefficient   of   linear expansions are\[{{\alpha }_{1}}\,\,and\,\,{{\alpha }_{2}}\]. If the difference between two lengths is independent of temperature-

A) \[\frac{{{\ell }_{1}}}{{{\ell }_{2}}}\,\,=\,\,\frac{{{\alpha }_{1}}}{{{\alpha }_{2}}}\]                

B) \[\frac{{{\ell }_{1}}}{{{\ell }_{2}}}\,\,=\,\,\frac{{{\alpha }_{2}}}{{{\alpha }_{1}}}\]

C) \[\ell _{2}^{2}{{\alpha }_{1}}\,\,=\,\,\ell _{1}^{2}{{\alpha }_{2}}\]                

D) \[\frac{\alpha _{1}^{2}}{{{\ell }_{1}}}=\frac{\alpha _{2}^{2}}{{{\ell }_{2}}}\]