The relationship between temperature and the rate of a photochemical reaction is governed by the Arrhenius equation, which states that the rate constant k of a reaction is proportional to the exponential of the negative activation energy Ea divided by the product of the gas constant R and the temperature T in Kelvin:k = A * e^-Ea / R * T where A is the pre-exponential factor, which represents the frequency of collisions between reactant molecules.As the temperature increases, the rate of a photochemical reaction generally increases as well. This is because higher temperatures provide more energy to the reactant molecules, allowing them to overcome the activation energy barrier more easily and increasing the probability of successful collisions that lead to the formation of products.However, it is important to note that photochemical reactions are also influenced by the presence and intensity of light, as they involve the absorption of photons to initiate the reaction. Therefore, the rate of a photochemical reaction depends not only on temperature but also on the availability of light energy.Regarding the activation energy of the reaction, it is generally considered to be constant for a specific reaction. However, the activation energy can be affected by the presence of catalysts, which lower the activation energy and increase the rate of the reaction. In some cases, temperature may influence the effectiveness of a catalyst or the stability of reaction intermediates, indirectly affecting the activation energy. But overall, the activation energy itself does not change significantly with temperature.