Final answer:
The energy released by nuclear fusion in the Sun's core takes between 100,000 and 1,000,000 years to reach the surface. This occurs due to the dense solar material and scattering of photons. Conversely, neutrinos created in the fusion process escape the Sun in just about two seconds.
Step-by-step explanation:
Is it a fast or slow process for the energy released by nuclear fusion to reach the surface of the sun? The journey of energy from the core of the Sun to its surface is a very slow process. Despite the high energy environment and the immense reaction rate of nuclear fusion at the Sun's core—where around 1038 protons convert to helium every second at temperatures of about 14 million Kelvin—the released energy primarily in the form of photons, takes a considerable amount of time to reach the Sun's surface. It is estimated that it takes approximately between 100,000 and 1,000,000 years for this energy to diffuse to the surface due to the dense solar interior and the complex path of absorption and scattering.
However, neutrinos, which are also produced in nuclear fusion reactions, can escape the Sun almost instantly as they interact so weakly with matter that the Sun is practically transparent to them. These neutrinos carry off a portion of the energy and can reach Earth in just over 8 minutes. Overall, the slow passage of energy through the solar interior provides a stable release that regulates the overall energy output of the Sun.