Answer:
12 Neutrons
Explanation:
So the mass of sodium is 22.990. You round it up to get 23(as stated in the problem). So, <em>what exactly is atomic mass?</em>
Atomic Mass is the total amount of neutrons and protons added up to form a total mass. So when you subtract 23-11 you get 12 Neutrons.
<u>Tip: </u>Don't know if you need this but-
The neutrons and protons are typically close in number (unless it's an isotope). So say that you subtract and the numbers of protons and neutrons aren't close at all. Well if that's the case, it's probably wrong.
hope this helps!!
Elastic potential energy is given by:
Where k is the spring constant in N/m and x is displacement from equilibrium position in m. Evaluating:
A/ The potential energy is stored in the spring is 44.1 J.
Gravitational potential energy is the energy stored in an object as the result of its vertical position or height. It can be calculated as its weight times the height. This is:
Where:
- W is the weight of the object
- m is the mass
- g is gravitational acceleration
- h is the height
Evaluating:
R/ The ball has 3.5525 J of potential energy.
We can solve the problem by using the law of conservation of energy:
- at the beginning, all mechanical energy of the object is just kinetic energy: 
, where m is the mass and v is the velocity
- at the point of maximum height, all mechanical energy of the object is just gravitational potential energy: 
, where h is the maximum height
Therefore, the conservation of energy becomes:
Re-arranging, we find the maximum height:
Answer:
5
Explanation:
λ (wavelength) = h (Plancks) / p (momentum)
also,
λ = h*c / ΔE so
h/p = (h * c) / ΔE
p * c (speed of light) = ΔE (in joules)
[ 0.5168 x 10^-27 kg m / sec ] * 2.998 x 10^8 m / sec = 1.55 J
Converting it to electron volts:
1.55 J / ( 1.602 x 10^-19 J / eV) = 0.97 eV for the photon energy
Using the Balmer Series:
ΔE = 13.6 eV [ 1 / Nf^2 - 1 / Ni^2]
0.97 / 13.6 = [ 1 / 3^2 - 1 / Ni^2 ]
0.07132 = [(1/9) - (1/Ni^2)]
0.07132 = [0.111 - (1/Ni^2)]
0.07132 - 0.111111 = - 1/Ni^2
-0.03979 = -1 / Ni^2
Ni^2 = 1/0.03979
Ni^2 = 25
Ni = 5
The use of Planck's constant is not necessary here.
N = 5 was the original energy level.
