How long does it take for a smoke detector to die once it starts beeping?
If you are referring to an intermittent beeping that is the battery low alarm, there is about a week of life left in the unit.
if the smoke is completely gone about 50 secs
It depends WHY it's beeping ! If it's beeping continuously, it's because you have overcooked something in the kitchen and smoke has got to the detector. Turn off the cooker and open some windows to provide ventilation to disperse the fumes. If there's no obvious cause, and it's a single beep followed by a long pause - it's probably due to the back-up battery being low - in which case, replace the battery !
It is used in smoke detectors as it cannot travel far in air. Alpha radiation is emitted and as long as the detector in the device is receiving the alpha radiation, then no smoke is present. When smoke particles are present, they interrupt the radiation, and so the detector doesn't pick up the radiation, causing the alarm to go off.
Is it normal for a 1998 Pathfinder to have white smoke coming from the exhaust when cold but not after the engine starts to warm up?
Statistically, non-smokers as a group will live significantly longer than smokers as a group, but this does not tell you as an individual how long you will live if you smoke. Suffice to say, if you would like to live as long as possible, then you definitely should not smoke. And really, there is no good reason to smoke. It is a senseless activity, with a high cost to both your physical and financial health…
That depends on how long and how much you smoke, and how old you are. At one extreme, no teenager ever died from smoking. At the other extreme, it starts to take a real toll once you reach your 50's. People who smoke for many years die on average several years before they would have if they had been non-smokers.