Question

Iodine-131 is a radioactive material that plays a role in natural gas production and has a half-life of 8 days. A 320-mg sample of iodine-131 will decay to 250 mg after approximately days.

Answer 1

Time of decays approximately 2.853 days

Further explanation

Given

mass = 320mg iodine-131

No=320 mg

Nt=250 mg

t1/2 = 8 days

Required

t=time of decays

Solution

General formulas used in decay:

`\large{\boxed{\bold{N_t=N_0((1)/(2))^{t/t(1)/(2) }}}`

Input the value

`\tt 250=320.(1)/(2)^(t/8)\\\\log(25)/(30)=t/8.log~0.5\rightarrow t=2.853~days`