Answer: 1000 Hz
Explanation:
You can calculate frequency by dividing velocity by wavelength
Frequency = velocity/wavelength
Find velocity first.
900 m/3 s = 300 m/s
Plug values in to find frequency.
F = (300 m/s)/0.3 m
F = 1000 Hz
Answer:

Explanation:
As we know that when electron moved in electric field then work done by electric field must be equal to the change in kinetic energy of the electron
So here we have to find the work done by electric field on moving electron
So we have



now the distance moved by the electron is given as

so we have



now we have to convert it into keV units
so we have


Answer:
The <em><u>n = 2 → n = 3</u></em> transition results in the absorption of the highest-energy photon.
Explanation:

Formula used for the radius of the
orbit will be,
where,
= energy of
orbit
n = number of orbit
Z = atomic number
Here: Z = 1 (hydrogen atom)
Energy of the first orbit in H atom .

Energy of the second orbit in H atom .

Energy of the third orbit in H atom .

Energy of the fifth orbit in H atom .

Energy of the sixth orbit in H atom .

Energy of the seventh orbit in H atom .

During an absorption of energy electron jumps from lower state to higher state.So, absorption will take place in :
1) n = 2 → n = 3
2) n= 5 → n = 6
Energy absorbed when: n = 2 → n = 3


Energy absorbed when: n = 5 → n = 6


1.89 eV > 0.166 eV
E> E'
So,the n = 2 → n = 3 transition results in the absorption of the highest-energy photon.