Question

e cần gấp ạ , e

Answer 1

Ta có: \(H=\dfrac{Q_{thu}}{Q_{toa}}100\%\Rightarrow Q_{toa}=\dfrac{Q_{thu}}{H}100\%=\dfrac{2\cdot75\cdot4200}{90\%}100\%=700000\left(J\right)\)

Lại có: \(Q_{toa}=A=UIt=Pt\Rightarrow t=\dfrac{Q_{toa}}{P}=\dfrac{700000}{1000}=700s\approx11,67mins\)

Ta có: \(P=\dfrac{U^2}{R}\Rightarrow R=\dfrac{U^2}{P}=\dfrac{220^2}{1000}=48,4\Omega\)

Lại có: \(R=p\dfrac{l}{S}\Rightarrow l=\dfrac{RS}{p}=\dfrac{48,4\cdot0,1\cdot10^{-6}}{5,5\cdot10^{-8}}=88m\)