Carbon-11 is one of the radioactive isotopes of carbon with half-life period of 20 minutes. What fraction of the initial number of c-11 atoms in a sample will have decayed away after 80 minutes ?.

Jim has found that he must consume 2,300 calories a day to reach his health goals, but he doesn't want to give up his afternoon snack of pretzels. unfortunately, he tends to eat the entire bag — which amounts to 1,300 calories! what strategy should jim use to improve his habits?

Auser wants to add a thick, dark green border around a chart in powerpoint. the user can do this in chart tools by choosing what

Earth takes in thermal energy from the sun in a process called . sunlight strikes earth’s surface at different angles. this angle is called the angle of . btw its