Answer:
Total time = 20 hours
Explanation:
Half life is the amount of time it takes for a substance to decay tohalf of it's original amount.
Half life = 5 hours.
We have to obtain the number of half lives to get the time required.
1st half life = 1/2
2nd half life = 1/4
3rd half life = 1/8
4th half life = 1/16
So ffour half lives.
Total time = number of half lives * Time of half life
Total time = 4 * 5
Total time = 20 hours
Answer:
20 hours
Explanation:
Using
R/R' = 2ᵃ/ᵇ.............................. Equation 1
Where R = Original amount of radioactive isotope, R' = Amount of radioactive isotope after disintegration, a = Total disintegration time, b = half life.
Note: The Fraction of original amount of radioactive isotope is 1.
Given: R = 1, R' = 1/16, b = 5 hours
Substitute into equation 1
1/(1/16) = 2ᵃ/⁵
16 = 2ᵃ/⁵
2⁴ = 2ᵃ/⁵
Equation the base
4 = a/5
a = 4×5
a = 20 hours
Hence the time = 20 hours
