Respuesta :
Explanation:
In case of bullet the Kinetic energy = 1/2 m v²
here m is the mass of bullet and v is its velocity .
When it penetrates through the board , the velocity of bullet decreases due to frictional force of board acting in opposite direction .
But in case of light photon K.E = h ν
here h is the Planck's constant and ν is the frequency of light wave .
When it passes through the glass , The wavelength λ of light decreases inside the glass .
The velocity of light c = ν λ , Because the frequency ν is the property of source , so it cannot be changed by the medium i.e glass .
Thus with the decrease of wavelength , the velocity decreases .
When light wave moves out of the glass , its wavelength again becomes the same . The velocity increases to its previous value .
That is the reason by which the light is emitted with the same velocity .
