Cho mạch điện như hình vẽ. r1=r3=3 ôm, r2=2 ôm, r4=1 ôm ,r5=4 ôm. cường độ dòng điện chạy qua mạch chính là 3A. tìm a) Uab
b)hiệu điện thế 2 đầu mỗi điện trở

Which is not a characteristic of a heat pump? a. it is used in air conditioners. b. it uses a refrigerant. c. it requires no work. d. it reverses the normal flow of thermal energy.

Apositive charge moves in the direction of an electric field. which of the following statements are true? check all that apply. check all that apply. 1.the potential energy associated with the charge decreases. 2. the electric field does positive work on the charge. 3. the electric field does negative work on the charge. 4. the potential energy associated with the charge increases. 5. the electric field does not do any work on the charge. 6. the amount of work done on the charge cannot be determined without additional information.

Acar travels 40m in 8 seconds find the car speed