Question

A clock with an iron pendulum keeps correct time at ${15}^{\circ }$C. What will be the error, in second per day, if the room temperature is ${20}^{\circ }$C? (The coefficient of linear expansion of iron is ${0.000012}^{\circ }{C}^{-1}$.)

• A. 2.6 s
• B. 6.2 s
• C. 1.3 s
• D. 3.1 s

Answer 1

The correct option is A 2.6 s

Here $△T$ = 20 - 15 = $5^{\circ }$C
$\alpha$ = ${0.000012}^{\circ }{C}^{-1}$ = 12 $\times {10}^{-6}{}^{\circ }{C}^{-1}$
Time lost per day = $\frac{1}{2}\alpha \left(△T\right)\times 86400s$
= $\frac{1}{2}\times 12\times {10}^{-6}\times 5\times 86400s$ = 2.590s