题目

In China, traveling by train is a common way to visit new places and go back to one’s hometown during holidays.【1】 It wasn’t always that way, though.【2】 Later, many railway companies started up and competed with each other to build new railway routes. Trains became a symbol of progress, with New York City’s Grand Central Station becoming a major cultural landmark(地标).【3】 For example, Johnny Cash wrote a song called Folsom Prison Blues.But little by little, railways were replaced by highways as “car culture” took over the US. China would go on to use trains even more w如图所示，R1=30Ω，R2=10Ω，闭合开关后，电流表的示数为0.1A．求：（1）R2的电流； （2）1min电路所消耗的总电能．