A bimetallic strip of thickness 2cm consists of zinc and silver riveted together. The approximate radius of curvature of the strip when heated through  ${50}^{0}C$ will be$(given {\alpha }_1,{\alpha }_2 are coefficients of linear expansion of zinc=32\times {10}^{-6}/{}^{0}C and silver=19\times {10}^{-6}/{}^{0}C)$

$$\begin{gathered} radius of curvature of a bimetallic strip when its temperature is changed through \Delta t is \\ R=\frac{d}{\left({\alpha }_1~{\alpha }_2\right)\Delta t}meter here d is strip width=2\times {10}^{-2}m; {\alpha }_1,{\alpha }_2 are coefficients of linear expansion of zinc=32\times {10}^{-6}/{}^{0}C and silver=19\times {10}^{-6}/{}^{0}C; \\ R=\frac{2\times {10}^{-2}}{\left(32\times {10}^{-6}-19\times {10}^{-6}\right)50} \\ R=\frac{2\times {10}^{-2}}{13\times {10}^{-6}\times 50} \\ R=\frac{2}{65}\times {10}^3=30.769 \\ R=30.77m \end{gathered}$$