Question

Answer 1

a) tóm tắt:

U1=12V

I₁=0,4 A

U₂=36V

I₂=? A

Ta có:\(\dfrac{U_1}{U_2}=\dfrac{I_1}{I_2}=>\dfrac{12}{36}=\dfrac{0,4}{I_2}=>I_2=1,2A\)

b) I₁ giảm 4 lần => I₂=0,1 A

ta có \(\dfrac{I_1}{I_2}=\dfrac{U_1}{U_2}=>\dfrac{0,4}{0,1}=\dfrac{12}{U_2}=>U_2=3V\)

Answer 2

a, \(\dfrac{U}{U'}=\dfrac{I}{I'}\Rightarrow I'=\dfrac{U'I}{U}=\dfrac{\left(12+36\right)\cdot0,4}{36}=\dfrac{8}{15}\left(A\right)\)

b,\(\dfrac{U}{U"}=\dfrac{I}{I"}\Rightarrow U"=\dfrac{U\cdot I"}{I}=\dfrac{U\cdot\dfrac{I}{4}}{I}=12\cdot\dfrac{1}{4}=3\left(V\right)\)