Two clocks are being tested against a standard clock located in a national laboratory. At 12:00:00 noon by the standard clock, the readings of the two clocks are :

If you are doing an experiment that requires 'precision time interval' measurements , which of the two clocks will you prefer ?

Explanation

The range of variation over the seven days of observations is 164 s for clock 1 , and 32 s for clock 2. The average reading of clock 1 is much closer to the standard time tan the average reading of clock 2. The important point is that a clock is zero error is not as significant for precision work as its variation , because a .zero-error. can always be easily corrected. Hence clock 2 is to be preferred to clock 1.