When a man travels from earth to space, the mass of the person, defined as the amount energy a matter has remains constant. However, when he moves to space, gravity decreases until such time that there is no gravity that acts on the person. Weight thus changes or decreases until the point of state called weightlessness.
It would protect best against C) Alpha radiation, as Beta radiation is stopped by lighter metals such as aluminium, and Gamma radiation can only be stopped by heavier metals such as lead.
They're elements. Elements are the simplest form of any substance that cannot be broken down by any chemical methods, including electrolysis or even heat. Examples include oxygen, hydrogen etc.
Answer:
The half-life of a radioisotope describes the amount of time it takes for said isotope to decay to one-half the original amount present in the sample.
Nitrogen-13, because it has a half-life of ten minutes, will experience two half-lives over the course of the twenty minute period. This means that 25% of the isotope will remain after this.
0.25 x 128mg = 32mg
32mg of Nitrogen-13 will remain after 20 minutes.
