Answer:
Explanation:
A pure substance is something that is entirely made up of particles that are identical to each other.
Any substance that is not pure, must be a mixture.
We are surrounded by mixtures. The air is a mixture of gases . The oceans are a mixture of (mainly) water and salt. The solid earth is mostly rock, which is a mixture of different minerals.
Natural resources are substances we need and use, which occur naturally. Some come from living things, (example) cotton other are non-living (example) sand.
The opposite of a natural resource is a made resource.
Answer:
One scientific law that provides the foundation for understanding in chemistry is the law of conservation of matter. It states that in any given system that is closed to the transfer of matter (in and out), the amount of matter in the system stays constant.
Explanation:
hope it helps ya
Answer:
the force will increase by a factor 2.25
Explanation:
The gravitational force between the two stars is given by:
where
G is the gravitational constant
m1, m2 are the masses of the two stars
r is the distance between the stars
If the distance is decreased by one-third, it means that the new distance is 2/3 of the previous distance
So the new force will be
So, the force will be 2.25 times the previous value.
Answer:
The acceleration is 11.25 km/hr
Explanation:
Divide the velocity over time to find the acceleration. The bus is accelerating 11.25 km/hr per second in the range of 8 seconds
Answer:
a) P=0.25x10^-7
b) R=B*N2*E
c) N=1.33x10^9 photons
Explanation:
a) the spontaneous emission rate is equal to:
1/tsp=1/3 ms
the stimulated emission rate is equal to:
pst=(N*C*o(v))/V
where
o(v)=((λ^2*A)/(8*π*u^2))g(v)
g(v)=2/(π*deltav)
o(v)=(λ^2)/(4*π*tp*deltav)
Replacing values:
o(v)=0.7^2/(4*π*3*50)=8.3x10^-19 cm^2
the probability is equal to:
P=(1000*3x10^10*8.3x10^-19)/(100)=0.25x10^-7
b) the rate of decay is equal to:
R=B*N2*E, where B is the Einstein´s coefficient and E is the energy system
c) the number of photons is equal to:
N=(1/tsp)*(V/C*o)
Replacing:
N=100/(3*3x10^10*8.3x10^-19)
N=1.33x10^9 photons
