a charged particle in an accelerated motion produces em radiation.
in an atom the electrons have accelerated motion.does it means that all electrons in atoms produce em

Yes. all the accelerating charged electron particles produces the Electromagnetic wave.  

Explanation:

Magnetic fields are produced during the movement of the charged particle. the magnetic field produced, will exert some force in the moving charges. The electric field as well as the magnetic field travelling in the empty space with respect of speed of light are the electromagnetic wave. Moving electron will always produce the magnetic field and thus the electrons motion are constant,but when the acceleration starts the electromagnetic waves are being radiated.

If you add soap or detergent in water, the surface tension of water changes, the molecular bond of water becomes weaker. So, when light hits a plain water, it could either be reflected, or the water gets heated and evaporates, and then forms into gas.

Explanation:

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