Answer: (E) 300 bq
Explanation:
Half life is the amount of time taken by a radioactive material to decay to half of its original value.
Radioactive decay process is a type of process in which a less stable nuclei decomposes to a stable nuclei by releasing some radiations or particles like alpha, beta particles or gamma-radiations. The radioactive decay follows first order kinetics.
Half life is represented by 
Half life of Thallium-208 = 3.053 min
Thus after 9 minutes , three half lives will be passed, after ist half life, the activity would be reduced to half of original i.e.
, after second half life, the activity would be reduced to half of 1200 i.e.
, and after third half life, the activity would be reduced to half of 600 i.e.
,
Thus the activity 9 minutes later is 300 bq.
Answer:
A) 20
B) 40
C) Ca
D) 10
E) 9
F) F
Explanation:
The MASS NUMBER is the number of protons + the number of neutrons.
The ATOMIC NUMBER is the number of protons.
You can take the MASS NUMBER - ATOMIC NUMBER = NUMBER OF NEUTRONS.
Each element is unique and distinguished by the NUMBER OF PROTONS = ATOMIC NUMBER, ie...the number of protons in its nucleus. You can find the element's name and symbol on the Periodic Table.
He was credited with discovering the subatomic particle also known as the electron in 1897.
Chromosomes have genes that determine specific thing about a person (hair color, eye color, how tall or short a person is etc....).