A freshly isolatedsample of 90Y was found to have an activity of 8.9 x 105 disintegrations per minute at 1:00pm on December 3, 2003. At 2:15pm on Dec, 17, 2003, its activity was redetermined and found to be 2.6 x 104 disintegrations per minute. Calculate the half-life of 90Y.

3960 minutes

Step-by-step explanation:

From;

0.693/t1/2 = 2.303/t log No/N

t1/2 = half life of 90Y

No = initial activity of 90Y =  8.9 x 10^5 disintegrations per minute

N= activity of 90Y after time t = 2.6 x 10^4 disintegrations per minute

t = time taken

Since the time elapsed is 20,235 minutes, we substitute into the formula above.

0.693/t1/2 = 2.303/20235 log 8.9 x 10^5/2.6 x 10^4

0.693/t1/2 =  1.75 * 10^-4

t1/2 = 0.693/ 1.75 * 10^-4

t1/2 = 3960 minutes

answer: if you weigh 60 pounds on earth, on the moon you will weigh about 10 pounds. if you weigh 120 pounds on earth, you will weigh about 20 pounds on the moon. since weight is caused by the mass of two objects that are near each other, the bigger the objects, the more the force of gravity.

step-by-step explanation: if you weigh 60 pounds on earth, on the moon you will weigh about 10 pounds. if you weigh 120 pounds on earth, you will weigh about 20 pounds on the moon. since weight is caused by the mass of two objects that are near each other, the bigger the objects, the more the force of gravity.

correct answer is c. just did it

step-by-step explanation: