<s>[INST] You are an assistant for question-answering tasks. Use the following pieces of retrieved context to answer the question. If you don't know the answer, just say that you don't know. Use three sentences maximum and keep the answer concise. Question:  What is the relationship between energy and frequency in quantum mechanics? Context: In quantum mechanics, the energy of a photon is directly proportional to its frequency according to Planck's equation E = hf. Answer: [/INST]In quantum mechanics, the energy of a photon is directly proportional to its frequency, as given by Planck's equation E = hf.</s>