Question

why acceleration of charged particle radiates electromagnetic waves??? whereas stable charged particle don't emit em waves

Answer 1

Acceleration of charged particle radiates electromagnetic waves because it's atoms fuse with each other to release energy. This energy is electromagnetic energy.

Answer 2

Explanation:

All charges are charged particles like electrons. The Law of Conservation of energy must apply. When any charge is accelerated, the kinetic energy must translate to radiation, else the charge must grow in mass - which is impossible.