Answer:

Explanation:
It is given that,
Diameter of cylinder, d = 6.6 cm
Radius of cylinder, r = 3.3 cm = 0.033 m
Acceleration of the string, 
Displacement, d = 1.3 m
The angular acceleration is given by :



The angular displacement is given by :



Using the third equation of rotational kinematics as :

Here, 



Since, 1 rad/s = 9.54 rpm
So,

So, the angular speed of the cylinder is 571.42 rpm. Hence, this is the required solution.
Answer:
When an electron is hit by a photon of light, it absorbs the quanta of energy the photon was carrying and moves to a higher energy state. One way of thinking about this higher energy state is to imagine that the electron is now moving faster, (it has just been "hit" by a rapidly moving photon)
A photon is a quantum of EM radiation. Its energy is given by E = hf and is related to the frequency f and wavelength λ of the radiation by. E=hf=hcλ(energy of a photon) E = h f = h c λ (energy of a photon) , where E is the energy of a single photon and c is the speed of light.
Dipper effect of an oncoming train get louder as it approaches and sound diminishes as it goes away sound traveling