忆江南

江南好，

风景旧曾谙。

___________，

___________。

能不忆江南？

实验桌上有一个电学器件，该器件由两个定值电阻R₁、R₂并联组成，且被封闭在一个透明的有机玻璃壳内，如图甲所示，a、b是该器件的两个外露接线柱，电阻R₁的阻值为20Ω，电阻R₂的额定电压为6V．科技小组同学测得通过该器件的电流I和其两端电压U的数值，并绘制成图乙所示的图象．

求：

（1）电阻R₂的阻值；

（2）电阻R₂的额定电功率．

2016年“世界环境日”中国确定的主题为“改善环境质量，推动绿色发展”．下列做法与之相违背的是（  ）

    A blocked airway(呼吸道) can kill someone in three to four minutes, but it can take more than eight minutes for an ambulance to arrive. So a simple procedure such as opening someone's airway can save their life while they're waiting for emergency medical help. This means you're more likely to give first aid to someone you know than a stranger.

    There are many misconceptions (误解) surrounding first aid. Below are the ‘most popular' ones with details of what you should do.

    You should put butter or cream on a burn. The only thing you should put on a burn is cold water — keep the butter for cooking. Put the affected area under cold running water for at least ten minutes.

    The best way to treat bleeding is to put the wound under a tap. If you put a bleeding wound under a tap you wash away the body's clotting agents(凝血剂) and make it bleed more. Instead put pressure on the wound with whatever is available to stop or slow down the flow of blood. As soon as possible call 999. Keep pressure on the wound until help arrives.

    Nosebleeds are best treated by putting the head back. If you put the head back during a nosebleed, all the blood goes down the back of the airway. Instead advise them to tilt(倾斜) their head forwards and ask the person to pinch(捏) the end of their nose and breathe through their mouth.

    You need lots of training to do first aid. You don't — what you mostly need is common sense. You can learn enough first aid in a few minutes to save someone's life — whether it's from a book, attending a course or watching videos online.

    Remember: anyone can save a life