How are electromagnetic waves produced

(a) How are electromagnetic waves produced ?
(b) How do you convince yourself that electromagnetic waves carry energy and momentum ?

(a) The electromagnetic waves are produced by the accelerated charge. The electric and magnetic fields produced by the accelerated charge change with time. Hence, it radiates electromagnetic waves.
(b)The EM waves are produced by the accelerated charge. The electron jumping from its outer to inner orbits radiates EM waves. These EM waves are propagated as electric and magnetic fields oscillating in mutually perpendicular directions which is cause of momentum and energy.