Question

Cat puteți plzz
Dau coroana

Answer 1

Se da:
r1=r2=r3=3Ω
P1=18W
U1=9V
a)I1=?A
b)E=?V
c)n=?
d)n'=80%=0,8; Q=37,8kJ=37800J; t=?s

Formule:
a)P1=U1*I1⇒I1=P1/U1

b)E=U+u

Putem observa ca U1 este defapt si tensiunea intre toate bateriile, de unde luam ca U=U1;

u=I*r

I=I1

r=r12+r3

Deoarece r1=r2, scoatem r12=r1/2

r=(r1/2)+r3
r=(r1/2)+r1
r=1,5r

E=U1+I1*1,5r

c)n=U/E⇔n=U1/E

d)n'=Q/L
L=Q/n'
P1*t=Q/n'
t=Q/P*n'

Calcule:
a)I1=18/9=2A
b)E=9+2*1,5*2=15V
c)n=9/15=0,6
d)t=37800/18*0,8=2625s