| lagging |
保溫套 |
| laminar flow |
層流 |
| laminated |
分層的，疊片的 |
| laser |
激光，激光器 |
| laser beam |
激光束 |
| laser material |
激光材料 |
| latch |
閂鎖 |
| latent heat |
潛熱 |
| lateral |
橫向，側向，旁向 |
| lateral inversion |
橫向倒置 |
| lateral magnification |
橫向放大，橫向放大率 |
| lateral search coil |
橫向探察線圈 |
| lattice |
點陣，晶格 |
| lattice spacing |
點陣間隔，點陣間距 |
| law |
定律 |
| law of conservation of momentum |
動量守恒定律 |
| law of reflection |
反射定律 |
| law of refraction |
折射定律 |
| lead |
導線，鉛 |
| lead-acid accumulator |
鉛酸蓄電池 |
| leakage current |
漏泄電流 |
| least distance of distinct vision |
最小明視距離 |
| Leclanche cell |
勒克朗謝電池 |
| length |
長度 |
| lens |
透鏡，晶體，晶狀體 |
| lens formula |
透鏡公式 |
| lens holder |
透鏡座 |
| lens marker' s formula |
透鏡製造者公式 |
| Lenz' s law |
楞次定律 |
| leukaemia |
白血病 |
| lever |
槓桿 |
| light |
光，光學 |
| light beam |
光束，光柱 |
| light dependent resistor |
光敏電阻器 |
| light emitting diode |
發光二極管 |
| light guide |
光導 |
| light pipe |
光導管 |
| light ray |
光線嶋綫 |
| light sensitive resistor |
光敏電阻器 |
| light source |
光源 |
| lightning |
閃電 |
| lightning conductor |
避雷針 |
| limiting angle |
極限角 |
| limiting friction |
極限摩擦 |
| line of action |
作用嶋 綫 |
| line of force |
力線嶋 綫 |
| line spectrum |
線狀光譜，線狀譜 |
| linear air track |
線性氣墊導航 |
| linear electronics |
線性電子學 |
| linear expansivity |
線性膨脹係數，線性脹率 |
| linear flow |
線流 |
| linear momentum |
線動量 |
| linear voltage amplification |
線性電壓放大率 |
| linearly polarized wave |
線偏振波 |
| liquefaction |
液化 |
| liquid |
液體 |
| liquid crystal |
液晶體 |
| liquid phase |
液相 |
| liquid pressure |
液體壓強 |
| liquid-in-glass thermometer |
玻管液體溫度計 |
| Lissajous figure |
利薩如圖形 |
| live |
載電，活線，火線嶋 |
| Lloyd' s mirror |
洛埃鏡 |
| load |
負荷 |
| lodestone |
磁石 |
| logic gate |
邏輯門 |
| logic level |
邏輯電平，邏輯級 |
| logic level indicator |
邏輯電平指示器，邏輯級指示器 |
| logic value |
邏輯值 |
| long sight |
遠視 |
| long wave |
長波 |
| longitudinal magnification |
縱向放大，縱向放大率 |
| longitudinal wave |
縱波 |
| loop |
回路，圈 |
| Lorentz force |
洛倫茲力 |
| Lorentz rotating disc |
洛倫茲旋轉盤 |
| loudness |
響度 |
| loudspeaker |
揚聲器 |
| low frequency a.c. generator |
低頻交流發電機 |
| low voltage |
低電壓 |
| low voltage immersion heater |
低壓浸沒式電熱器 |
| lower limit |
下限 |
| lycopodium powder |
石松粉 |
| Lyman series |
賴曼系，賴曼光譜 |
