How many times did the original sample lose 50% of its radioactivity ?
-- Start with. . . . . . . . . . . . 12 grams.
-- Lose half of it once. . . . . . 6 grams left.
-- Lose half of it again . . . . . 3 grams left.
-- Lose half of it again . . . . . 1.5 grams left.
-- Lose half of it again . . . . . 0.75 gram left.
-- How many times did it lose half ? 4 times.
-- How long does it take to lose half ? 4.5 days.
(That's why it's called the 'half-life'.)
-- How long did it take to lose half, 4 times ?
(4 x 4.5 days) = 18 days .
Answer:
Explanation:
For n-=1 state hydrogen energy level is split into three componets in the presence of external magnetic field. The energies are,
,
,
Here, E is the energy in the absence of electric field.
And
are the highest and the lowest energies.
The difference of these energies
is known as Bohr's magneton.
B=2.5 T,
Therefore,
Now,
Therefore, the energy difference between highest and lowest energy levels in presence of magnetic field is
Answer:
the pe at the top of the building: 784 J
the pe halfway through the fall: 392 J
the pe just before hitting the ground: 784 J
Explanation:
Pls brainliest me
I had this question before
Finding acceleration= final speed-initial speed/time taken (or A=V-U\T)
Finial speed= 27.8s
Initial speed= 0s
Time taken= 5.15
So..
27.8-0/5.15= 5.40m/s (rounded to two decimal places)
Answer:
Isotopes are the elements having the same atomic number i.e same number of protons which in turn is equal to same number of electrons. Number of protons and electrons are equal as the atom is electrically neutral. So, the only option is A.
I hope it helps you !
