Question

Answer 1

Bài 6:

\(P=I^2R=2,5^2\cdot80=500\)W

\(H=\dfrac{Q_{thu}}{Q_{toa}}100\%=\dfrac{1,5\cdot4200\cdot75}{500\cdot20\cdot60}100\%=78,75\%\)

Answer 2

Câu 5:

\(MCD:R1ntR2\)

\(\left\{{}\begin{matrix}R=R1+R2=25+15=40\Omega\\I=I1=I2=U:R=12:40=0,3A\end{matrix}\right.\)

\(R2=p2\dfrac{l2}{S2}=>l2=\dfrac{R2\cdot S2}{p2}=\dfrac{15\cdot0,06\cdot10^{-6}}{0,5\cdot10^{-6}}=1,8\left(m\right)\)