A pendulum clock loses 12s in a day if the temperature is 40°C and gains 4s in a day if the temperature is 20°C. The temperature at which the clock will show correct time, and the coefficient of linear expansion (α) of the metal of the pendulum shaft are respectively :-
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Question

A pendulum clock loses 12s in a day if the temperature is 40°C and gains 4s in a day if the temperature is 20°C. The temperature at which the clock will show correct time, and the coefficient of linear expansion (α) of the metal of the pendulum shaft are respectively :-

Options

G1 Physics · Accepted Answer

Use ΔL=αLΔT, ΔA≈2αAΔT and ΔV≈3αVΔT (or the given cubical coefficient γ). For constrained bodies include the elastic stress needed to cancel free expansion. Evaluating the given data/statements gives 25°C ; α = 1.85 ×10⁻⁵ /°C. Therefore the correct answer is B.