Question

How many grams the gamma emitter l-125 remain after 240 days if you started with 100.00g and the half life is 60 days?

Answer 1

Answer:

6.23 g.

Explanation:

From the question given above, the following data were obtained:

Original amount (N₀) = 100 g

Time (t) = 240 days

Half life (t½) = 60 days

Amount remaining (N) =?

Next, we shall determine the decay constant (K). This can be obtained as follow:

Half life (t½) = 60 days

Decay constant (K) =.?

Decay constant (K) = 0.693/Half life (t½)

K = 0.693/60

K = 0.01155 /day

Finally, we shall determine the amount of gamma emitter l-125 that remains after 240 days as follow:

Original amount (N₀) = 100 g

Time (t) = 240 days

Half life (t½) = 60 days

Decay (K) = 0.01155 /day

Amount remaining (N) =?

Log (N₀/N) = kt/2.3

Log (100/N) = (0.01155 × 240)/2.3

Log (100/N) = 2.772/2.3

Log (100/N) = 1.2052

Take the anti log of 1.2052

(100/N) = antilog (1.2052)

100/N= 16.04

Cross multiply

100 = N × 16.04

Divide both side by 16.04

N = 100/16.04

N = 6.23 g

Therefore, the amount of the gamma emitter l-125 that remains after 240 days is 6.23 g