如图，已知R₁=R₂=…=R_n=R_n+1=…=R_m=R_m+1…= $\frac{1}{2}R$ ，R=40Ω，电源电压60V，流过R_n的电流大小是____．

    There are a lot of Chinese cultures about fish. In Chinese, “fish” sounds like “surplus”（余），Chinese people always like to have a surplus at the end of the year. They think if they save something at the end of the year, then they can make more in the next year. That's why Chinese people like to eat fish for the New Year. Do you know what kind of fish Chinese people like to eat for the New Year?

Crucian carp

    The first kind of fish is crucian carp. It sounds like the Chinese word“吉”. The Chinese word mean “good luck”. Chinese people think that eating crucian carp can bring good luck for the next year.

Chinese mud carp

    The second kind of fish is Chinese mud cap. It sounds like the Chinese word“礼”. It means gifts or presents. So, Chinese people choose to eat Chinese mud carp during the Chinese New Year. It means “good future”.

Catfish

    The third kind of fish is catfish. It sounds like two Chinese words “年余”.So eating catfish is a wish for a surplus in the New Year.