Question

A clock battery wears out after moving 87780 C of charge through the clock at a rate of 42 mA. How many days before the batteries run out?

Round your answer to 2 decimal places

Answer 1

We can find the number of days before the battery runs out from the formula:

$$Q=It,$$ $$t=\dfrac{Q}{I},$$ $$t=\dfrac{87780\ C}{42\cdot10^{-3}\ A}=2.09\cdot10^6\ s\cdot\dfrac{1\ h}{3600\ s}\cdot\dfrac{1\ day}{24\ h}=24\ days.$$