Part A How many years are required for the amount of krypton-85 in a spent nucle
ID: 1486200 • Letter: P
Question
Part A
How many years are required for the amount of krypton-85 in a spent nuclear reactor fuel rod to be reduced by a factor of 1/8? The half-life of krypton-85 is 10.8 years.
Express your answer using three significant figures.
t1/8 = ______ years
Part B
How many years are required for the amount of krypton-85 in a spent nuclear reactor fuel rod to be reduced by a factor of 1/32?
Express your answer using three significant figures.
t1/32 = ______ years
Part C
How many years are required for the amount of krypton-85 in a spent nuclear reactor fuel rod to be reduced by a factor of 1/128?
Express your answer using three significant figures.
t1/128 = ______ years
Explanation / Answer
The half-life of krypton-85 is 10.8 years.
That means, in 10.8 years amount of krypton-85 gets reduced by a factor of 1/2.
Now,
Part A How many years are required for the amount of krypton-85 in a spent nuclear reactor fuel rod to be reduced by a factor of 1/8?
To get reduced to 1/8, it requires 3 half-lifes. i.e. 1/2 * 1/2* 1/2 = 1/8
Therefore, t1/8 = 3 * 10.8 = 32.4 years.
Part BHow many years are required for the amount of krypton-85 in a spent nuclear reactor fuel rod to be reduced by a factor of 1/32?
To get reduced to 1/32, it requires 5 half-lifes. i.e. 1/2 * 1/2* 1/2 *1/2 * 1/2= 1/32
Therefore, t1/32 = 5 * 10.8 = 54 years.
Part C How many years are required for the amount of krypton-85 in a spent nuclear reactor fuel rod to be reduced by a factor of 1/128?
To get reduced to 1/128, it requires 7 half-lifes. i.e. 1/2 * 1/2 * 1/2 * 1/2* 1/2 *1/2 * 1/2= 1/128
Therefore, t1/32 = 7 * 10.8 = 75.6 years
Calculations shall be verified once, logic used is correct.
Hope this helps :)