A pendulum clock keeps correct time at 0∘. Its mean coefficient of linear expansions is α/∘, then the loss in seconds per day by the clock if the temperature rises by t∘ is
12αt×86400
Loss in time per second △TT=12α△θ=12α(t−0)
⇒loss in time per day
△T=(12αt)t=12αt×(24×60×60)=12αt×86400