One of the harmonics of a column of air in a tube that is open at one end and closed at the other has a frequency of 448 Hz, and
1 answer:
Answer:
1.34 m
Explanation:
For an open-end tube, the frequency difference between two consecutive harmonics is equal to the fundamental frequency of the tube:
In this case, we have
so, the fundamental frequency is
For an open-end tube, the fundamental frequency is also given by:
where v is the speed of sound and L the length of the tube.
Since we know v = 343 m/s, we can solve the formula for L:
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The atom must lose 2 electrons
Explanation:
An atom consists of three types of particles:
- Protons, in the nucleus, with positive electric charge
- Neutrons, in the nucleus, with no electric charge
- Electrons, orbiting around the nucleus, with negative electric charge
As a result, the net electric charge of an atom is given by the number of protons minus the number of electrons:
Q = #p - #e
For a neutral atom, the number of protons and electrons is the same, so the net charge is zero.
In order for an atom to have a positive charge of +2, it means that there must be 2 protons more than the number of electrons. Since atoms exchange electrons (and not protons), this means that the atom must have "lost" 2 electrons.
In this problem, we have an atom with 13 protons: this means that initially it also has 13 electrons. However, later the atom lost 2 electrons, and as a result, the final charge is +2e.
Learn more about atoms:
#LearnwithBrainly
Part A)
First of all, let's convert the radii of the inner and the outer sphere:
The capacitance of a spherical capacitor which consist of two shells with radius rA and rB is
Then, from the usual relationship between capacitance and voltage, we can find the charge Q on each sphere of the capacitor:
Now, we can find the electric field at any point r located between the two spheres, by using Gauss theorem:
from which
In part A of the problem, we want to find the electric field at r=11.1 cm=0.111 m. Substituting this number into the previous formula, we get
And so, the energy density at r=0.111 m is
Part B) The solution of this part is the same as part A), since we already know the charge of the capacitor:
. We just need to calculate the electric field E at a different value of r: r=16.4 cm=0.164 m, so
And therefore, the energy density at this distance from the center is
First of all, let's convert the radii of the inner and the outer sphere:
The capacitance of a spherical capacitor which consist of two shells with radius rA and rB is
Then, from the usual relationship between capacitance and voltage, we can find the charge Q on each sphere of the capacitor:
Now, we can find the electric field at any point r located between the two spheres, by using Gauss theorem:
from which
In part A of the problem, we want to find the electric field at r=11.1 cm=0.111 m. Substituting this number into the previous formula, we get
And so, the energy density at r=0.111 m is
Part B) The solution of this part is the same as part A), since we already know the charge of the capacitor:
And therefore, the energy density at this distance from the center is