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.

Please show all work and answer all THREE questions.

Part A

How many disintegrations per second does this level of activity imply?

Part B

If each alpha particle deposits 8×10?13J of energy and if the average person weighs 71 kg , calculate the number of rads and rems of radiation in 4 yr from such a level of plutonium.

(Clearly I got the answer but I don't actually understand what it means, please explain)

Part C (not pictured)

Answer from part B in rem instead of rad. What does that mean???

Explanation / Answer

Part A -

Average quantity of radioactivity = 2pCi

1Ci = 3.7 x1010 dps

2pCi = 2*10-12 * 3.7 x1010 dps

= 7.4x 10-2 dps

Part B -

1 rad = 0.01 J/kg

Energy / particle = 8x10-13 J

time = 4 yrs

number of partcles = 0.074 x (3600) x 24 x 365 x 4

n = 9334656

E = nE = 9334656 x 8 x 10-13

= 7.467 x 10 -6 J

man weight = 71 kg

number of radons = E / weight

= 0.01x 7.467 x10-6 / 71

= 1.05 x10-9

1 rem = 100 rad

number of rem = 1.05 x10-9 / 100

= 1.05 x10-11

Part C -

The rem is the unit used for equating radiation absorption with biological damage.

Since absorption of radiation can damage tissue, a way to measure that damage and ensure that it is kept to a minimum is necessary. The amount of radiation Energy absorbed in a body is known as dose. The special unit for measuring dose in a person (called dose-equivalent) is the rem.

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