Time standards are now based on atomic clocks. A promising second standard is ba

Question

Time standards are now based on atomic clocks. A promising second
standard is based on pulsars, which are rotating neutron, stars (highly compact stars
consisting only of neutrons). Some rotate at a rate that is highly stable, sending out a radio
beacon that sweeps briefly across Earth once with each rotation, like a lighthouse beacon.
Pulsar PSR 1937 + 21 is an example; it rotates once every 1.557 806 448 872 75 ±3 ms,
where the trailing ±3 indicates the uncertainty in the last decimal place (it does not mean ±3
ms). (a) How many times does PSR 1937 + 21 rotate in 7.00 days? (b) How much time does
the pulsar take to rotate 1.0 * 10^6 times?

Explanation / Answer

a.

there are 24 hours per day, and there are 60 minutes in an hour and there are 60 seconds in an hour so in 7 days there are:

7*24*60*60=604800[sec]=604800000[msec]

the pulsar rotates once every 1.55780644887275±3 [msec] it does 1/(1.55780644887275±3)=

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