题干

在如图的电路中,电源电压恒为12V,定值电阻R0为50Ω,滑动变阻器的最大值为50Ω,小灯泡上标有“6V”字样,不考虑灯丝电阻变化.若开关S、S1、S2都闭合,当滑片P在b端时,电流表示数为____A.若开关S闭合,S1、S2都断开,当滑动变阻器接入电路的阻值为20Ω时,电流表的示数为0.4A,则小灯泡的额定电功率是____W.

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0.48,1.2

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D

    To control the nation's growing problem with food wastage, the South Korean government has started a special initiative (倡议) ---“Pay as You Trash”. According to the initiative, the South Korean government has three methods in place to charge citizens for the food thrown away. One is through an RFID (Radio Frequency Identification) card — when users tap this card over a specially designed food waste bin, the lid will open. This waste is automatically weighed and recorded in the user's account. The user needs to settle this bill every month.

    The second billing method is through pre-paid garbage bags. These specially designed bags are priced based on the amount of space. For instance, in Seoul, a 10-liter garbage bag costs around 190 won (less than $1). There's also a bar code management system in place, in which residents (居民) throw food waste directly into dustbins and pay for it by buying bar code stickers attached to the bin.

    Even before the pay-by-weight system was introduced, South Koreans were still being charged for food waste — the cost was simply divided equally among the residents of each apartment block. The new system is not only fair, but is also designed to make consumers really feel the pinch of too much waste. The more food they throw out, the more they end up paying.

    Thanks to the initiative, residents like Seoul housewife Ms. Kwan are now adopting creative methods to avoid food waste. She makes sure to pour all the liquid out of leftover food before throwing it away. While preparing vegetables, she tries to use as much as the eatable parts as possible in order to reduce waste.