题型概述：波动与热学Question types: waves and thermal
IPC 的这类题把波动关系与日常热现象结合起来：A 部分常用选择题检查不变量和比例，B 部分要求把材料、传热机制与现象串成解释。本组选三道 A 题（各 1 分）和两道 B 题（各 5 分），共 13 分。常见失分是把频率和声速混为一谈、把温升当终温，以及只列“传导、对流、辐射”却不说明结构为何有效。B 题原文保留，文字解答供自查；自动评分使用明确标出的附加数值检验。IPC connects wave relationships with everyday thermal phenomena. Section A checks invariants and ratios; Section B asks for causal explanations linking materials, mechanisms and observations. This set has three A questions (1 mark each) and two B questions (5 marks each), totalling 13. Common errors confuse frequency with speed, temperature rise with final temperature, or name heat-transfer mechanisms without explaining the structure. Original written questions are retained; auto-grading uses clearly labelled additional numerical checks.
1波速、频率、波长Speed, frequency and wavelength
先判断什么保持不变：波跨过静止边界时频率由声源固定；同一介质内改变声源频率时，声速近似不变。First identify the invariant: crossing a stationary boundary preserves source frequency; changing source frequency in the same medium approximately preserves speed.
MHz 要乘 10⁶；波长换成 mm 要乘 1000。Multiply MHz by 10⁶ and metres by 1000 to obtain mm.
2升温与冷却Heating and cooling
恒功率绝热加热产生恒定温升速率；自然冷却中，温差变小会使净热损失减小。Constant-power insulated heating produces a constant heating rate; during natural cooling, smaller temperature differences reduce net heat loss.
摄氏温差与开尔文温差数值相同。Celsius and kelvin temperature differences have the same numerical value.
3材料如何改变传热How materials change heat flow
泡沫的低导热率、封闭小孔和反光箔分别作用于不同机制。解释题要把每一项结构对应到物理原因。Low foam conductivity, closed cells and shiny foil act on different mechanisms. Link each structural feature to its physical cause.
辐射式的四次方温度必须用 K；低发射率表面应面对间隙。Use kelvin for fourth-power radiation temperatures; low-emissivity surfaces should face a gap.
| 子题型Sub-type | 识别特征Clue | 核心步骤Core step | 真题Question |
|---|---|---|---|
| 跨温区传播Propagation across temperatures | 深水变冷Colder at depth | 固定 f，再比较 vFix f, compare v | 2025 A6 |
| 成像分辨率Imaging resolution | 频率提高Higher frequency | 求 λ = v/fUse λ = v/f | 2025 A9 |
| 恒功率加热Constant-power heating | 同块、同加热器Same block and heater | 比较 ΔT/tCompare ΔT/t | 2022 A9 |
| 自然冷却Natural cooling | 曲线渐平Flattening curve | 温差→热流→斜率Difference → heat flow → gradient | 2017 B12 |
| 建筑保温Building insulation | 泡沫夹亮箔Foam and shiny foil | 结构对应传热机制Match structure to mechanism | 2023 B11 |