Answer:
25% thorium will left after 50 days.
Explanation:
Half life:
A nuclear half is the time period of radioactive material in which its amount remain halved.
In given question it is stated that the half life thorium-234 is 25 days. Which means after passing the 25 days the amount of thorium must be halved of original amount.
For example,
If the original concentration was 100%, than after 25 days it will be 50%.
After 50 days amount of thorium left:
Number of half life = T (elapsed) / T half life
Number of half life = 50/25
Number of half life = 2
At first half life amount of thorium left = 100/2 = 50
After second half life amount of thorium left = 50/2 = 25
Total amount decayed = 50+25 = 75
Amount left after 50 days = 100-75 = 25
25% thorium will left after 50 days.
Answer:
Cabon-12 has same average atomic weight and mass number.
Explanation:
carbon-12 has average atomic weight 12 amu and mass number of 12.
amu represents average of mass of a nucleon.
As carbon-12 has same average atomic mass and mass number therefore carbon-12 is a good standard to determine average mass of a nucleon.
Again, abundance of carbon-12 isotope is almost equal to 99%. Therefore fluctuation of average atomic weight from 12 amu is very very low.
So, carbon-12 is taken as a standard to determine mass of a nucleon.
Hence atomic mass of carbon-12 is 12 amu.
I think it might be D or B
And my other two might be A or C
Answer:
The length of foil will be 8107.81 cm or 81.7081 m.
Explanation:
Given data:
Width of roll of foil = 302 mm
Height or thickness = 0.018 mm
Density of foil = 2.7 g/cm³
Mass of foil = 1.19 Kg
Length of foil = ?
Solution:
d = m/ v
v = length (l) × width (w) × height (h)
First of we will convert the Kg into gram and mm into cm.
one Kg = 1000 g
1.19 × 1000 = 1190 g
one cm = 10 mm
302 / 10 = 30.2 cm
0.018 / 10 = 0.0018 cm
Now we will put the values in formula:
d = m/ l× h× w
l = m / d × h× w
l = 1190 g / 2.7 g/cm³× 30.2 cm × 0.0018 cm
l = 1190 g/ 0.146772 g/cm
l = 8107.81 cm or 81.7081 m
Ok I may be young but combine the two reactions to create a compund
