Tests on human subjects in Boston in 1965 and 1966, following the era of atomic

Question

Tests on human subjects in Boston in 1965 and 1966, following the era of atomic bomb testing, revealed average quantities of about 2 pCi of plutonium radioactivity in the average person.

A.) How many disintegrations per second does this level of activity imply? (answer is 7x10^-2 dis/s)

B.) If each alpha particle deposits 8×1013J of energy and if the average person weighs 79 kg , calculate the number of rads and rems of radiation in 5 yr from such a level of plutonium. (units are rad)

C.) Express your answer using one significant figure. (units are rem)

Thank you so much in advance!

Explanation / Answer

A)

the activity is 7.4 x 10-2 disintegrations per second

B)

now

time = 5 yr = 1.578 x 10^8 seconds

now

number of disintegrations = activity x time

number of disintegrations = 7 x 10-2 x 1.578 x 10^8

number of disintegrations = 1.1046 x 10^7

now

for every disintegration , energy is 8 x 10-13 J

so

total energy = 1.1046 x 10^7 x 8 x 10-13

total energy = 8.8368 x 10-6

now

dose = energy / mass

dose = 8.8368 x 10-6 / 79

dose = 1.12 x 10-7 J / Kg

now

we know that

1 rad = 0.01 = J / Kg

so

dose = 1.12 x 10-5 x 10-2 J / Kg

dose = 1.12 x 10-5 rad

so

number of rads = 1.12 x 10-5 rad

C)

now

for alpha radiations

1 rad = 20 rem

so

dose = 1.12 x 10-5 x 20 rem

dose = 2.24 x 10-4 rem

so

number of rem = 2.24 x 10-4 rem

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.