1.

The co-efficient of thermal expansion of a rod is temperature dependent and is given by the formula `alpha = aT`, where `a` is a positive constant at T `"in"^(@)C`. if the length of the rod is l at temperature `0^(@)C`, then the temperature at which the length will be `2l` isA. `sqrt((1n2)/alpha)`B. `sqrt((1n4)/alpha)`C. `1/(alpha)`D. `2/alpha`

Answer» Correct Answer - B
As, `dl=alpha l dT :. underset(l)overset(2l)(int) (dl)/(l) = a underset(0)overset(T)(int) T dT`
`1n 2 = a(T^2)/(2) :. T = [ (1n 4)/(a)]^(1//2)`.


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