# Bimetallic strip

A metal strip of length $$l_0 = 20 \,\text{cm}$$ consists of a layer of iron (Fe) and a layer of zinc (Zn), which are welded together with each having a thickness of $$d = 2\,\text{mm}$$. At a temperature of $$T = 0\, ^\circ\text{C}$$, the bimetallic strip is completely straight.

What is the radius of the curvature $$r$$ of the strip at a temperature of $$T = 100\, ^\circ\text{C}?$$

The respective thermal expansion coefficients of zinc and iron are

$\alpha_\text{Zn} = 3\cdot 10^{-5}/^\circ\text{C},\quad \alpha_\text{Fe} = 1\cdot 10^{-5}/^\circ\text{C}.$

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