Phosphorus - 32 is a reaction isotope used as a tracer in the liver. How much ph
ID: 527391 • Letter: P
Question
Phosphorus - 32 is a reaction isotope used as a tracer in the liver. How much phosphorus 32 was originally used if there is only 3.50 mg left in a sample after 288 h? (The half life of phosphorus 32 is 14.3 days) A. 1.96 mg B. 4.17 mg C. 6.26 mg D. 7.00 mg Tritium (^3 H) is used in glowing "EXIT" signs located where there is no electricity for light bulbs. If the half life of tritium is 12.26 years, what percentage of the original quantity of the isotope is left in the sign after 18.5 years? A. 0.632% B. 25.0% C. 35.1% D. 63.2% Radiation seed therapy is a common method for treating some prostate cancers and brain tumors. Palladium -103, with a half life of 17 days, is one isotope used for this treatment. How long does it take for the activity of palladium - 103 to decrease to 1.0 % of its initial value and essentially cease to be effective?Explanation / Answer
Q17
find P original if
P left = 3.5 mg, t = 288 h
HL = 14.3 days = 14.3*24 h = 343.2 h
now
A = A0*(0.5)^(t/HL)
3.5 = A0 * (0.5)^(288 /343.2 )
3.5/0.5589 = A0
A0 = 6.2623 mg