Đáp án:
\(\begin{array}{l}
1.\\
a.l = 56,25m\\
b.I = \dfrac{1}{3}A\\
c.Q = 3000J\\
d.P = 5W\\
2.R = 45\Omega \\
3.{U_{\max }} = 15V
\end{array}\)
Giải thích các bước giải:
\(\begin{array}{l}
1.\\
a.\\
R = p\frac{l}{S}\\
\Rightarrow l = \dfrac{{RS}}{p} = \dfrac{{45.0,{{5.10}^{ - 6}}}}{{0,{{4.10}^{ - 6}}}} = 56,25m\\
b.\\
I = \dfrac{U}{R} = \dfrac{{15}}{{45}} = \dfrac{1}{3}A\\
c.\\
Q = UIt = 15.\frac{1}{3}.600 = 3000J\\
d.\\
P = UI = 15.\frac{1}{3} = 5W\\
2.\\
Q = R{I^2}t\\
\Rightarrow R = \dfrac{Q}{{{I^2}t}} = \dfrac{{108000}}{{{2^2}.600}} = 45\Omega \\
3.\\
{I_{1\max }} = \dfrac{{{U_{1\max }}}}{{{R_1}}} = \dfrac{{10}}{{10}} = 1A\\
{I_{2\max }} = \dfrac{{{U_{2\max }}}}{{{R_2}}} = \dfrac{8}{5} = 1,6A\\
\Rightarrow {I_{\max }} = {I_{1\max }} = 1A\\
R = {R_1} + {R_2} = 10 + 5 = 15\Omega \\
{U_{\max }} = {I_{\max }}R = 1.15 = 15V
\end{array}\)
