Question

Giúp tui câu b thui. Nêu rõ cách tính I₂(i₂) Nha

Answer 1

a) R12=\(\dfrac{R1\times R2}{R1+R2}\)=\(\dfrac{10\times15}{10+15}\)=6(Ω)

R\(_{tđ}\)=R12+R3=6+6=12(Ω)

I\(_{AB}\)=\(\dfrac{U_{AB}}{R_{tđ}}\)=\(\dfrac{12}{12}\)=1(A)

vì R12 nt R3 =>IAB=I12=I3=1(A)

U12=I12\(\times\)R12=1\(\times\)6=6(V)

Mà R1//R2=>U12=U1=U2=6(V)

I2=\(\dfrac{U_2}{R_2}\)=\(\dfrac{6}{15}\)=0.4(A)

b)P=\(I_{AB}^2\times R_{tđ}\)=1\(\times\)12=12(W)

P\(_2\)=I\(_2\)\(\times\)R\(_2\)=0.4\(\times\)15=6(W)

đổi 15'=0.25s

A=P\(\times\)t=12\(\times\)0.25