If a 100 gram sample of a radioactive material with a half-life of 10 years decays for 20 years
will remain
?

25 gram left

Explanation:

Given data:

Total mass = 100 g

Half life of radioactive material = 10 years

Mass left after 20 years = ?

Solution:

First of all we will calculate the number of half lives passed during 20 years.

Number of half lives = time elapsed / half life

Number of half lives = 20 years / 10 years

Number of half lives = 2

At time zero 100 g present.

At first half life = 100 g/2 = 50 g

At 2nd half life = 50 g/2 = 25 g

Thus, after 20 years 25 gram of radioactive material left.

answer is: nuclear fusion produces elements that are heavier than helium.

nuclei combine to form a heavier nucleus, releasing energy.  

for example, fusion of hydrogen atoms at the sun.  

this fusion nuclear reaction is in the inner core of the sun and hydrogen (atomic number 1) is conveted into helium (atomic number 2).  

the inner core is the central region of the sun and all solar energy is produced in the core by nuclear fusion.  

the correct answer would be b. amelia, because the particals of gas move really fast (charged particals) and gas also has a lot of room (particals move independently) so the only answer that has both of those is amelia's.