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:
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Answer:
the energy of an electron and the most probable distance of the electron from the nucleus.
Explanation:
The principal quantum number, n, describes the energy of an electron and the most probable distance of the electron from the nucleus. In other words, it refers to the size of the orbital and the energy level an electron is placed in. The number of subshells, or l, describes the shape of the orbital.
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Answer: Land absorbs heat energy and releases heat energy quickly. Water absorbs heat energy and releases heat energy slowly. Global convection currents are set up in the atmosphere because of the unequal heating of Earth's surfaces.
