Question

Why don't electrons radiate energy when revolving in discrete orbits?

Answer 1

According to the classical mechanics, orbits are shells of constant energy in which electrons revolve. These energy shells are considered to be of a discrete energy value and electrons radiate energy when they make transitions from one shell to another. But they do not radiate any energy while revolving.

Therefore, as electron revolve, it does not produce wavelets because, it do not spin about its on axis/center, so they does not radiate.