When light is traveling away from a black hole, its wavelength becomes longer. This is called blue-shifting. If it's going in, the wavelength becomes shorter, which is called red-shifting.
If the photon frequency is below the threshold frequency, the electrons do not have enough energy to be emitted from the material's surface, and no photoelectric effect occurs. The electrons will not be ejected and will remain bound to the material.
what is resonant frequency
Frequency Increases
As wavelength increases the frequency decreases.
To calculate the frequency of the light emitted when an electron in a hydrogen atom makes a transition, simply use change in E = (-2.18*10^-18 J)[1/(nf)^2 - 1/(ni)^2]. Then convert the energy E to frequency using f = E/h where h is Planck's constant 6.626*10^-34 J*s.
the frequency reduces in value. The longer the wavelength the lower the frequency.
The initial atom is transformed in another atom.
Fluorescence. It happens when atoms' electrons absorb light at one frequency and emit at other (usually lower) frequencies. Sometimes two photons are absorbed by the same electron, and emitted as a single higher frequency, but this is not common.
I assume you mean the frequency at which the head moves back and forth. If this happens only at a certain frequency, then it sounds as if that is caused by resonance - which happens when the excitation (in this case, the head moving back and forth) has a similar frequency to the object's (the printer's) natural frequency.
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When the source of a sound is moving toward you, the sound waves emitted by the source are compressed, resulting in a higher frequency of the sound you hear. This phenomenon is known as the Doppler effect and is commonly experienced with sirens from emergency vehicles approaching you.
Frequency is how often something happens.