Final answer:
The internal temperature of a McMuffin round egg with a gelled yolk after cooking should be 160°F. For the oil heated on a hot plate, the oil's temperature will be 150°C, the same as the hot plate. The final temperature of a spoon placed in coffee can be determined using heat transfer calculations.
Step-by-step explanation:
When eggs are cooked to make a McMuffin, the internal temperature of the eggs with a gelled yolk should reach about 160°F which ensures that the eggs are fully cooked and safe to eat without being overcooked. According to food safety guidelines, eggs should be cooked until the yolks and whites are firm to prevent the risk of foodborne illness. The temperature of 160°F is hot enough to achieve this texture.
In a thermal equilibrium situation, if a pan of oil is on a hot plate and they are in thermal contact, the oil will eventually reach the same temperature as the hot plate, assuming no heat is lost to the surroundings. In the given scenario, the temperature of the oil will be 150°C, matching the temperature of the hot plate at thermal equilibrium.
For a scenario where an aluminum spoon is placed in hot coffee, the final temperature of the two in equilibrium would be between the initial temperatures of the spoon and the coffee but closer to the coffee's initial temperature due to its greater mass and heat capacity. Assuming coffee has the same specific heat as water, the final temperature can be calculated using the concept of heat transfer between the spoon and the coffee.