9) (3/4)*(1/4)/(3/4 + 1/4)=0,75 (С)
10) Q=I²*R1*t + I²*R2*t (A)
11) Q=U²*t/R (C)
12) Рп=F*v=4000*5=20 кВт Рз=I*U=100*500=50 кВт n-20/50=0.4 40% (B)
14) q=I*t=0.8*60=48 Кл N=48/(1.6*10^-19)=3*10^20 (A)
15) m*g*h=10*10*5=500 Дж (A)
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