A half life pertains to the time it takes for exactly half of a substance to disappear. So, if U235 has a half life of 700 million years, it will take 700 million years for half of it to decay. That would leave .5kg or 500g.
Uranium 235, with a half-life of 700 million years1, will decay to 0.95x10-6 of its original value after 14 billion years, and to 0.25 of its original value after 1400 million years.
AT = A0 2(-T/H)
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1The actual half-life of 235U92 is 704 million years. The answer given used 700, not 704.
Since that is exactly 2 times the half-life, 1/4 (that is, 1/2 x 1/2) of the original amount will be left.
50 % from the initial quantity
The half-life is 700 million years !
The fraction that remains is 1/8.
The original only remains in its original location when the copy command is used. The move command would move the original to a new location.
One-half of the original amount. That's precisely the definition of "half-life".
The height to which a dropped ball rebounds is typically significantly greater than the height of the ball. Also, incidentally, the height of the ball usually doesn't change during the event, and remains equal to its original height.
After two half-lives, 25% of an isotopes original number of atoms remains. AT = A0 2 (-T/H) Where A0 is the original activity, AT is the activity after some time T, and H is the half-life in units of T, so ... A2 = A0 2 (-2/1) A2 = 0.25 A0
1/8 of the original amount remains.
One eighth remains.
A quarter remains.
2
8.4
1/32
The fraction that remains is 1/8.
3.88 billion years
It remains an improper fraction.
Yes, it is false that dinosaur footprints are original remains.
An eighth remains.
20 percent of the original remains of the Philippine forest