A steel bridge in a town is 200 m long . Where minimum temperature in winter is `10^(@)C` and maximum in summer is `40^(@)C` . The change in length of bridge from winter to summer is [for steel `alpha = 11 xx 10 ^(-6//@)C`]

Options

A. 3.3 cm
B. 6.6 cm
C. 6.6 m
D. 8.3 m

Answer

B

Explanation

Coefficient of linear expansion ,
`alpha = (l_(2) - l_(1))/(l_(1)( t_(2)- t_(1)))`
`implies Delta l = l_(1)alpha (t_(2)-t_(1))`
`implies Delta l = 200 xx 11 xx 10^(-6) xx(40-10)`
`therefore Delta l = 0.066 m = 6.6 cm`