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An Introduction to Thermodynamics phần 5

Tương tự như vậy, để cơ thể hấp thụ một số tiền nhất định của năng lượng nhiệt ở nhiệt độ T 2, nó có thể tạo được ít nếu bất kỳ sự khác biệt cho nhà nước, hoặc dữ liệu ngẫu nhiên của cơ thể, nơi năng lượng đến từ. Đồng thời, chúng ta phải nhận ra chúng tôi đã giới thiệu một xấp xỉ bằng cách giả định việc chuyển giao năng lượng nhiệt năng chuyển giao trong điều kiện cân bằng. . | Similarly to the body absorbing a certain amount of thermal energy at the temperature T2 it can make little if any difference to the state or entropy of the body where the energy came from. At the same time we must recognize we have introduced an approximation by assuming the energy transfer was thermal energy transfer under equilibrium conditions. If for example the energy is transferred by radiation higher-temperature radiation has a greater chance of knocking electrons free as photoelectrons so the state of the receptor may depend at least to some extent on the temperature of the higher-temperature radiator. The closer the experimental situation approaches true equilibrium the more assurance we can have that the answers are adequate. For example in the paragraph preceding equation 6 in which thermal energy is transferred to the system ice from the surroundings a thermostat at a slightly higher temperature there is no reason to doubt the conclusions. Problems 1. Figure 5 shows a capillary tube dipping into a dish of water. The tubing is bent and water dripping from the suspended open end turns a paddle wheel before returning to the dish. By covering the apparatus water can be retained and the energy required is returned to the dish by thermal conduction from the surroundings. What is wrong FIGURE 6 Each small magnet on the wheel is aligned with its north pole outward in this perpetual-motion machine. 2. Figure 6 shows a wheel on which are mounted small bar magnets. The force between the fixed magnet and the individual magnets attached to the wheel may be taken as proportional to 1 d where d is the distance separating the magnets. Show that the force between the fixed magnet and the nearest magnet is smaller than the sum of the forces pulling the magnets along the right-hand side. That is 1 d1 1 d2 1 d3 . A magnetic shield readily available is placed as shown. The wheel then rotates counterclockwise. What is wrong 7 10 07 2- 53 3. Find AS when 2 mol of an ideal .