# Which halflife formula is correct?

• huan.conchito
In summary, the halflife formula is commonly used in scientific calculations to determine the remaining amount of a radioactive substance at a given time. It is represented as N(t) = N0 * (1/2)^(t/t1/2), where N(t) is the remaining amount, N0 is the initial amount, and t1/2 is the half-life of the substance. Different halflife formulas exist for different types of radioactive substances and each isotope has its own unique halflife. The formula can only provide an estimate for the time of decay and is used in practical applications such as nuclear medicine, environmental studies, and dating techniques.
huan.conchito

is it
Al = Ao(1/2)^(t/h)
or
Al = Ao(1/2)^(h/t)
?
where Ao =original amount
Al = amount left

Last edited:
Well, what do YOU think? Suppose t were equal to 2h.

The first formula gives AI= Ao(1/2)^(2h)= Ao((1/2)^h)^2 which is less than the amount at the half life.

The second formula gives AI= A0(1/2)^(h/2)= A0((1/2)^h)^(1/2) which is more than the amount at the half life.

If you let this (radioactive subtance?) sit longer, will it gain or lose mass?

after time t
t = time
h = half-life

The correct half-life formula is Al = Ao(1/2)^(t/h), where Ao is the original amount, Al is the amount left after time t, t is the time, and h is the half-life. This formula is derived from the exponential decay equation, which shows the relationship between the amount of a substance remaining and the time passed. It is important to use the correct formula to accurately calculate the half-life and understand the rate at which a substance decays.

## 1. What is the halflife formula used in scientific calculations?

The halflife formula commonly used in scientific calculations is: N(t) = N0 * (1/2)^(t/t1/2), where N(t) is the remaining amount of a radioactive substance at a given time t, N0 is the initial amount of the substance, and t1/2 is the half-life of the substance.

## 2. Are there different halflife formulas for different types of radioactive substances?

Yes, there are different halflife formulas for different types of radioactive substances. The formula used depends on the type of decay the substance undergoes, such as alpha, beta, or gamma decay.

## 3. Is the halflife formula the same for all radioactive isotopes?

No, the halflife formula is not the same for all radioactive isotopes. Each isotope has its own unique halflife, which is determined by its nuclear properties.

## 4. Can the halflife formula be used to predict the exact time of decay for a radioactive substance?

No, the halflife formula can only provide an estimate for the amount of time it takes for a radioactive substance to decay. The actual time of decay for a specific substance is unpredictable and can only be determined through observation.

## 5. How is the halflife formula used in practical applications?

The halflife formula is used in a wide range of practical applications, such as in nuclear medicine, environmental studies, and dating techniques. It allows scientists to determine the rate of decay of a substance and make predictions about its behavior over time.

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