The lifetime of a π⁺ meson normally is 18 nanoseconds.In a large particle accelerator,scientists can create π⁺ mesons moving at speeds very close to the speed of light.What do the scientists observe when they measure the lifetime of a π⁺ meson that is created at very high speed?
A)The π⁺ meson lasts 18 nanoseconds.
B)The π⁺ meson lasts much more than 18 nanoseconds.
C)The π⁺ meson lasts much less than 18 nanoseconds.
D)The π⁺ meson no longer decays and remains as a stable particle.

Question

Quizplus · Accepted Answer

The scientists observe that the π⁺ meson lasts much more than 18 nanoseconds due to the effects of time dilation, a prediction of Einstein's theory of relativity. As the speed of the meson approaches the speed of light, time appears to slow down for it from the perspective of an observer, thus increasing its observed lifetime.

The Lifetime of a π⁺ Meson Normally Is 18 Nanoseconds