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Do all exponential functions show growth over time?
If the exponent has the variable of time in it, then it will be either exponential growth (such as compound interest for example), or exponential decay (such as radioactive materials, or a capacitor discharging). If the time constant (coefficient of the time variable) is positive then it is growth, if the time constant is negative, then it is decay.
What is the difference between exponential and nonexponential decay?
Perhaps a good way to explain the difference between exponential and nonexponential decay (like perhaps linear decay) would be to use some examples. In radioactive decay, which is exponential decay, the rate of decay is a function of the amount of material present. The more you have to start with, the more decays per unit of time. The less you begin with the smaller that number of decay events in a given period. And as the decay continues the number of decay events per unit of time decreases. (A consequence is that the material might never be seen to all "go away" in time.) Radioactive decay is a function of the amount of material undergoing decay, and the rate of decay is exponential. That is, when we write the equations for the phenomenon, we'll be using exponents in the expressions to account for the dependence of the decay rate on the amount of material present. There is a good comparison to this. Let's say a group of students is in a classroom and leaves at the bell. The all get up and hit the door, but the rate at which the students can get out is basically a function of the width of the doorway, and not how many students are trying to get out. This is easy to see. If the students go through the door at one student per second and 30 students were in the class, it will take 30 seconds for them to all leave. The rate of "decay" of the population in the room is constant at one student per second. It does not change. It was the same when all the students were trying to get out, and remains constant even as the last couple of students are trying to exit. It is a nonexponential "decay" scheme, and is, in fact, a linear one. The equation expressing the egress phenomenon will not have any exponents in it; all the terms will be what are called first order terms. No "powers" of a number or variable will appear. (A consequence is that the room will empty of students, and definitely so. This is a contrast to radioactive decay.)
What are examples of Poisson's distribution?
Radioactive decay of unstable atomsTelephone calls arriving at a switchboardPhotons arriving at a telescopeMutations on a given strand of DNA
What is meaning of exponent with variable?
That you have an exponential function. These functions are typical for certain practical problems, such as population growth, or radioactive decay (with a negative exponent in this case).
How much of radioactive substance remains after 15 hours if it's half life is 5 hours?
The half-life of a radioactive substance is the time that it takes for half of the atoms to decay. With a half-life of 10 days, half has decayed in this time. After 20 days, a further 10 days/another half life, a further half of the remainder has decayed, so 1/4 of the original material remains, 1/4 of 15g is 3.75 grams. This is the amount of original radioactive substance remaining, but it’s daughter isotope ( what the decay has produced ) is also present, so the original sample mass is effectively constant, especially in a sealed container. Even in an unsealed container, and assuming alpha ( helium nucleii) emission, a drop in mass per radioactive atom of 4 Atomic Mass units, compared with the original atom of, say 200 amu is only 2% mass decrease, less for heavier decaying nucleii.
