解这道题---**Extraction Content:** **Question Stem:** 14. 如图所示, 电源电压恒为 12 V, R₀ = 20 Ω, 滑动变阻器的规格为“20 Ω 1 A”, 电流表的量程为“0~3 A”, 小灯泡上标有“4 V 2 W”的字样, 灯丝电阻保持不变, 为保证电路各元件正常安全使用, 则 **Circuit Diagram Description:** Type: Electrical circuit diagram. Main Elements: * Power supply (battery symbol, positive on top, negative on bottom). * Main switch S, in series with the positive terminal. * Resistor R₀, in series with switch S. * A junction after R₀, where the circuit splits into two parallel branches. * Branch 1 (Upper): Ammeter A, in series with switch S₁, in series with light bulb L (labeled L), in series with sliding rheostat R₁ (labeled R₁). The slider on R₁ is shown at an intermediate position. * Branch 2 (Lower): Switch S₂, in series with resistor R₀ (a second resistor labeled R₀). * The two parallel branches (Upper and Lower) join and connect back to the negative terminal of the power supply. * Ammeter A is in the upper branch containing the light bulb and sliding rheostat. **Options:** A. 当闭合 S, 断开 S₁, S₂ 时, 滑动变阻器接入电路的最小值是 12 Ω B. 当闭合 S, 断开 S₁, S₂ 时, 滑动变阻器的电功率最大值为 4.5 W C. 当 S, S₁, S₂ 都闭合时, 电路消耗的总功率最大值为 19.2 W D. 当 S, S₁, S₂ 都闭合时, 滑动变阻器的阻值取值范围是 16 Ω~20 Ω **Other Relevant Text/Data:** * 电源电压恒为 12 V (Power supply voltage is constant 12 V) * R₀ = 20 Ω * 滑动变阻器的规格为“20 Ω 1 A” (Sliding rheostat specifications: 20 Ω, 1 A) * 电流表的量程为“0~3 A” (Ammeter range: 0~3 A) * 小灯泡上标有“4 V 2 W”的字样 (Small light bulb labeled "4 V 2 W") * 灯丝电阻保持不变 (Filament resistance remains unchanged) * 为保证电路各元件正常安全使用 (To ensure safe operation of all components)