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.
Total atoms is 9 ( 2 carbon atoms, 5 hydrogen atoms, 1 oxygen atom and 1 hydrogen atom = 9 atoms)
Element is 3 ( Carbon, Hydrogen and Oxygen)
Heat energy can be calculated by using the specific heat of a substance multiplying it to the mass of the sample and the change in temperature. It is expressed as:
Energy = mCΔT2520= 10.0(C) (70.0 - 10.0)C = 4.2 J/ kg K
Answer:
D
Explanation:
the production of an odor would indicate that the heat ignited a chemical reaction
Answer:
B
Explanation:
Because when a cold object is cold it start to get warm because Of the air.
and it start to warm and it gets warm.