According to quantum theory the radiation must appear in the form of:

Explanation

According to quantum theory, radiation must appear in the form of discrete packets of energy called quanta (or photons).Here's a breakdown:Classical Physics (before quantum theory): Classical physics described light as a continuous wave. This model couldn't explain certain phenomena like blackbody radiation and the photoelectric effect.Quantum Theory: Max Planck proposed that energy is not emitted or absorbed continuously but in discrete packets called quanta. Albert Einstein later extended this idea to light itself, suggesting that light consists of particles called photons, each carrying a specific amount of energy.The energy of a photon is given by the equation:E = hf