Question

Cho mạch điện như hình vẽ

Trong đó UAB=6V, R1=2Ω,R2=R3=4Ω. Số chỉ ampe kế là

1A

0,5A

0,75A

0,25A

Answer 1

a,\(R_{23}=\dfrac{R_2R_3}{R_2+R_3}=\dfrac{4\cdot4}{4+4}=2\left(\Omega\right)\)

\(R_{TĐ}=R_1+R_{23}=2+2=4\left(\Omega\right)\)

\(I_1=I_{23}=I=\dfrac{U_{AB}}{R_{TĐ}}=\dfrac{6}{4}=1,5\left(A\right)\)

\(U_2=U_3=U_{23}=I_{23}R_{23}=1,5\cdot2=3\left(V\right)\)

\(I_A=I_3=\dfrac{U_3}{R_3}=\dfrac{3}{4}=0,75\left(A\right)\)

Answer 2

R1 nt(R2//R3)

\(\Rightarrow I1=\dfrac{U}{R1+\dfrac{R2R3}{R2+R3}}=1,5A=I23\)

\(\Rightarrow U23=U3=I23R23=3V\Rightarrow Ia=I3=\dfrac{U3}{R3}=\dfrac{3}{4}A=0,75A\)