Answer:
100 grams of C-14 decays to 25 grams in 11,460 years.
The C-14 isotope is only useful for dating fossils up to about 50,000 years old
If an ancient bone contains 6.25% of its original carbon, then the bone must be 22,920 years old.
Explanation:
We already know that the half life of C-14 is 5,730 years. After the first half life, we have 50 grams remaining. This takes 5,730 years. After the second half life (11,460 years now gone) we have 25 grams of C-14 left.
If a fossil material is older than 50,000 years an undetectable amount of 14C is left in the sample hence Carbon-14 is no longer suitable for dating the sample.
From;
0.693/5730 = 2.303/t log (No/0.0625No)
Where;
t = time taken and No = initial amount of C-14
0.693/5730= 2.77/t
t = 22,920 years
Answer: Option (B) is the correct answer.
Explanation:
Elements of a group represent similar chemical properties because they contain same number of valence electrons which determines their reactivity.
Hence, elements of a group have same chemical nature or property.
A group is represented by a vertical column in a periodic table.
On the other hand, a period is represented by a horizontal line.
Thus, we can conclude that a column contains elements with similar properties in the periodic table.
The scientist that invented a model that shows the electron cloud is Neil Bohr. <span />
Answer:
Explanation:
uestion
If an atom of an element has a mass number of 45 and it has 20 neutrons in its nucleus, what is the atomic number of the
element?
Answer:
C. A ball dropped from a height of 10 m will hit the ground at a higher speed than an identical ball dropped from a height of 5 m.
Explanation:
The statement of the hypothesis is that " the greater the height from which you drop a ball, the faster the ball will be traveling when it hits the ground because gravity has more time to speed it up ".
The hypothesis statement is quite explicit. We can deduce that objects at a higher height above the ground will hit the ground much more faster and harder compared to those at a shorter height.
A ball at height of 10m is expected to drop with a higher speed on the ground compared to an identical ball at a height of 5m.
If the balls are at the same height, they are expected to fall with the same speed so far they are identical. Also, a ball at a shorter height will fall at a lower speed.
