a. \(R=p\dfrac{l}{S}\Rightarrow l=\dfrac{R.S}{p}=\dfrac{20.0,5.10^{-6}}{5,5.10^{-8}}=181,\left(81\right)m\)
\(R'=R1+R_{bt}=10+20=30\Omega\)
\(\left(R1ntR_{bt}\right)I1=I_{bt}=I=U:R'=9:30=0,3A\)
\(\Rightarrow U_{bt}=I_{bt}.R_{bt}=0,3.20=6V\)
Đúng 0
Bình luận (0)
