A substance has a half-life of 10,000 years and an initial mass of 1,000 grams. How many years will pass before only 250 grams o
2 answers:
Answer:
A).
Explanation:
Half life is the total time after which the substance will decay and remains only half of the initial amount
So here we will say that
initial amount is 1000 gram
Now after one half life only half of the amount will remain
so it is
now again after another half life it will remain half of the initial amount
so it is
so it took two half lives
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Explanation:
The electro magnetic force is given by
F =
where and
are charged particles
k =Coulombs constant
r = distance between two charges
And gravitational force is given by
F =
where and
are masses
G =Garvitation constant
r = distance between two masses
Now since the planets, stars and galaxies are electrically neutral, therefore they have zero electrical charge and so electro magnetic forces have no affect on these planets, stars and heavenly bodies.
Whereas the masses of the heavenly bodies are very large, so they are largely affected by the gravitational force since Gravitational force is directly proportional to the product of the masses of a body.
Therefore, though the electromagnetic force is stronger than the gravitational force, the electromagnetic force does not dominate the forces in the heavenly bodies as they as not electrically charged.
Answer:
The maximum no. of electrons-
Solution:
As per the question:
Maximum rate of transfer of charge, I = 1.0 C/s
Time, t = 1.0 h = 3600 s
Rate of transfer of charge is current, I
Also,
Q = ne
where
n = no. of electrons
Q = charge in coulomb
I = current
Thus
Q = It
Thus the charge flow in 1. 0 h:
Maximum number of electrons, n is given by:
where
e = charge on an electron =
Thus