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In 5 years, radioactivity reduces the mass of a 100-gram sample of an element to 75 grams. Find the constant k for this element for t in years, the write the equation for modeling this exponential decay

Respuesta :

E
=
h
f
=
6.626
×
10

34
J

s
×
5.00
×
10
14
s

1
=
3.31
×
10

19
J
The energy is
3.31
×
10

19
J
.

          Value of constant 'k' = -0.041097

          Equation modeling the exponential decay → [tex]\text{ln}\frac{N}{N_0}=-0.41097t[/tex]

Rule for the radioactive decay:

  • Rule for the radioactive decay is given by the expression,

         [tex]\text{ln}\frac{N}{N_0}=-kt[/tex]

         Here, N = Amount remaining after 't' years

                   N₀ = Initial amount of the radioactive element

                    k = Constant

                    t = Period of decay

Given in the question,

  • N = 100 gms
  • N₀ = 75 gms
  •  t = 5 years

Substitute these values in the expression for the value of 'k',

[tex]\text{ln}\frac{75}{100}=-7k[/tex]

[tex]k=\frac{1}{7}[(\text{ln}(75)-\text{ln}(100)][/tex]

[tex]k=\frac{1}{7}[4.317488-4.605170][/tex]

k = -0.041097

Equation modeling the exponential decay → [tex]\text{ln}\frac{N}{N_0}=-0.41097t[/tex]

  Therefore, value of constant 'k' = -0.041097

               Equation modeling the exponential decay → [tex]\text{ln}\frac{N}{N_0}=-0.41097t[/tex]

Learn more about the radioactive decay here,

https://brainly.com/question/9660135?referrer=searchResults