A pendulum clock having copper rod keeps correct at $\;20^{0} C\;.$ It gains 15 seconds per day if cooled to $\;0^{0}C\;.$ Calculate the coefficient of linear expansion of copper :

Question

$(a)\;{2.6 \times 10^{-5}} ^{0}{C^{-1}}\qquad(b)\;{1.6 \times 10^{-5}} ^{0}{C^{-1}}\qquad(c)\;{2.7 \times 10^{-5}} ^{0}{C^{-1}}\qquad(d)\;{1.7 \times 10^{-5}} ^{0}{C^{-1}}$