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1 Primary & Middle School Physics1–9 年级在线 2 High School Physics10–12 年级在线 3 University Physics — Year 1本科一年级在线 4 University Physics — Year 2本科二年级在线 5 University Physics — Year 3本科三年级在线

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1 Markets I: The Ecosystem and Exchange-Traded Markets市场在线 2 Markets II: Rates, FX and Credit市场在线 3 Markets III: Commodities, Energy and Crypto市场在线 4 Quantitative Methods方法在线 5 Derivatives and Volatility衍生品在线 6 Rates, Credit, XVA and Risk利率、信用与风险在线 7 Research Craft: Predictors, Backtests, Measurement, Portfolios研究在线 8 Strategies I: Equities and Futures策略在线 9 Strategies II: Volatility, Relative Value, Macro and the Bank Desks策略在线 10 Microstructure and Execution交易执行在线 11 Market Making and High-Frequency Trading做市在线 12 Machine Learning for Markets机器学习在线 13 Low-Latency Software技术在线 14 Networks, Hardware and Trading Infrastructure技术在线 15 Research, Data and Risk Platforms技术在线 16 The Desk and the Firm公司运营在线 17 The Industry: Firms, Roles and Careers职业发展在线 18 Interviews I: Maths, Probability and Speed职业发展在线 19 Interviews II: Markets, Trading Games and the Final Round职业发展在线 20 Interviews III: Code职业发展在线

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Physics · 术语表

什么是 Joule effect？

又称： fuse

Definition 12.14 High School Physics · 第 12 章 — Electric Circuits and Power

The dissipation $P = RI^2$ turning electrical energy into heat in every resistor is the Joule effect. Heaters, kettles, toasters and old-style bulbs are resistors by design; a fuse is a thin wire calibrated to melt — opening the circuit — when the current exceeds its rating.

The delivery of : raising U at fixed P = UI shrinks I, and the loss falls with I2. — The delivery of Example 12.15: raising $U$ at fixed $P = UI$ shrinks $I$ , and the loss falls with $I^2$ .

示例

Example 12.15 (Why pylons run high)

A village needs $P = 100\,\mathrm{kW}$ through a line of resistance $R_\ell = 5.0\,\Omega$ . Delivered at $U = 500\,\mathrm{V}$ : $I = P/U = 200\,\mathrm{A}$ and the line wastes $R_\ell I^2 = 200\,\mathrm{kW}$ — twice the delivery: absurd. At $U = 20\,\mathrm{kV}$ : $I = 5.0\,\mathrm{A}$ and $R_\ell I^2 = 125\,\mathrm{W}$ . Forty times less current, $1600$ times less loss.

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