Question

Помогите пожалуйста срочно с меня 60 баллов хоть 3 задачи

Answer 1

Ответ:

Объяснение:

1)

$I = \dfrac q t \Rightarrow t = \dfrac q I = \dfrac{50*10^{-6}}{0.2*10^{-3}} = 0.25~c$

2)

$I = \dfrac U R = \dfrac U {\rho\dfrac l S} = \dfrac{US}{\rho l} = \dfrac{3*0.02}{0.017*2.2} = 1.6~A$

3)

$Q = I^2Rt = 5^2 * 20000*900 = 450\,000\,000~J = 450~MJ$

4)

$R = \dfrac{(R_1+R_2)*(R_3+R_4)}{R_1+R_2+R_3+R_4} = \dfrac{(15+35)*(20+20)}{15+35+20+20} = 22.22~Om$

$I_1 = \dfrac{U_1}{R_1} = \dfrac{30}{15} = 2~A\\\\I_2 = I_1 = 2~A\\\\U_2 = I_2R_2 = 2*35 = 70~B\\\\U_{12} = U_{34} = U_1 + U_2 = 30+70 = 100~B\\\\I_3 = I_4 = \dfrac{U_{34}}{R_3 + R_4} = \dfrac{100}{40} = 2.5~A\\\\U_3 = I_3R_3 = 2.5*20 = 50~B$