1. Frequency: 
The frequency of a light wave is given by:

where
is the speed of light
is the wavelength of the wave
In this problem, we have light with wavelength

Substituting into the equation, we find the frequency:

2. Period: 
The period of a wave is equal to the reciprocal of the frequency:

The frequency of this light wave is
(found in the previous exercise), so the period is:

Well first you can not go to the 2nd energy level without the first so the first takes up 2 electrons leaving you 5 electrons and the recommended amount is 8 electrons so you would have 5 electrons left
Answer:
d = 0.71 meters
Explanation:
It is given that,
Charge 1, 
Charge 2, 
Electrostatic force between charges, F = 9 N
Let d is the distance between the charges. The electrostatic force between the charges is given by the product of charges and divided by square of distance between them. Mathematically, it is given by :



d = 0.71 meters
So, the distance between the charges is 0.71 meters. Hence, this is the required solution.
It will be approximately equal.
<h3>How will the final kinetic energy change?</h3>
We can infer that all of the energy in the electron is Potential energy (PE) because the energy provided by the photon is hardly enough to outweigh the work function.
It will gain kinetic energy (KE) as it advances in the direction of the anode because it is moving through an electric field. All of the PE will have been transformed to KE by the time it reaches the anode.
According to the question
K = hf - W
W = Work function
The energy of photons is comparable. After conversion, there was only a little amount of KE remaining.
Therefore, PE (W) essentially equals KE (K).
It will about be equal.
Learn more about work function here:
brainly.com/question/19595244
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Use the equation in the physics reference sheet. You can use the distance formula