Half life is the time taken by a radioactive isotope to decay by half its original mass.
The original mass is 200 g
Time taken is 60 hours
Final mass is 25 g
Therefore;
Final mass = Original mass × (1/2)^n; where n is the number of half lives.
25 = 200 (1/2)^n
1/8 = (1/2)^n
n = 3
Three half lives = 60 hours
1 half lives = 20 hours
Therefore; the half life of the radioactive nucleus is 20 hours
Hi the answer your looking for is C, muscle: bone to bone connection.
Hope this helps you.
Answer:
The contributions are not listed in the question. I guess the following are the options you are talking about.
Same elements have same properties:
In 1803 Dalton gave the atomic theory that the properties of the atoms of the same element are same.
Electrons in Orbits:
Electrons were discovered in 1897 by J J. Thompson but the hypothesis of electrons in the orbits were given by Hantaro Nagaoka in 1904.
Plum pudding model:
Plum pudding model was given by J. J. Thompson in 1904 with the concept of positively charged medium containing the negatively charged electrons in it.
Positively Charged Atomic Nucleus:
Earnest Rutherford in 1911 discovered the positively charged atomic nucleus.
Answer:
The heat of the solution of salt is 1.66.11 J/g.
Explanation:
Mass of the water = m = 46.52 g
Initial temperature of the water = 
Final temperature of the water = 
The specific heat of water, c = 4.180 J/gºC
Heat associated with water on dissolving salt: q
Negative sign means that heat was lost by water on an addition of a salt.
Heat released on dissolving of salt = -Q = 748.65 J
Mass of salt added = 4.5069 g
Heat of the solution of salt :
= 
The heat of the solution of salt is 1.66.11 J/g.
