The process through which excess light energy is dissipated in photosynthesis is called quenching. Quenching refers to the ability of plants to dissipate excess energy from sunlight in order to prevent damage to the photosynthetic apparatus. When plants receive more light than they can use for photosynthesis, they employ various mechanisms to prevent the accumulation of excess energy. One such mechanism is quenching, which involves the conversion of excess light energy into heat energy. This helps to protect the photosynthetic pigments from being overwhelmed and damaged by the excess energy. Scavenging, on the other hand, refers to the process of removing harmful reactive oxygen species produced during photosynthesis. Photolysis is the breaking apart of molecules using light energy, and photophosphorylation is the process of using light energy to produce ATP. Therefore, the correct answer is option 1.