A: Can I help you?
B: Yes. The green scarf is very pretty. How much is it?
A: It's $100.
B: It's too expensive. What about the sunglasses?
A: They're $20.
B: They're cheap. I like them.
如图所示的电路中,电阻R1的阻值为10Ω,电源电压不变.当开关S接1时,电压表的示数为8V,电流表的示数为1.2A.求:
(1)R2的阻值是多少?
(2)当开关S接2时,若通电1min,电阻R2产生的热量是多少?