Element X decays radioactively with a half life of 6 minutes. If there are 790 grams of Element X, how long, to the nearest tenth of a minute, would it take the element to decay to 35 grams?

Respuesta :

Answer:

It will take 27 minutes.

Step-by-step explanation:

Let the exponential decay function is, [tex]y = a(b)^{x}[/tex], where a is the initial value and b is the rate of decay.

Now, 6 minutes is the half-life of the radioactive element.

So, [tex]\frac{a}{2} = a(b)^{6}[/tex]

⇒ [tex]b^{6} = 0.5[/tex]

b = 0.891 (Approximate)

Now, if y = 35 grams and a = 790 grams, then we can write

[tex]35 = 790(0.891)^{x}[/tex]

⇒ [tex]0.044 = (0.891)^{x}[/tex]

Now, taking log in both sides, we get

log (0.044) = x log (0.891)

⇒ x = 27 minutes.

Therefore, it will take 27 minutes. (Answer)