Vom folosi urmatoarea formula pentru n generatoare legate in paralel:
[tex] \frac{E_e}{r_e} =\sum_{i=1}^n \frac{E_i}{r_i}[/tex]
Pentru 2 generatoare legate in paralel, formula va fi:
[tex] \frac{E_e}{r_e}= \frac{E_1}{r_1} + \frac{E_2}{r_2}= \frac{E_1r_2+E_2r_1}{r_1r_2} [/tex]
[tex]E_1=E\\
r_1=r\\
E_2=2E\\
r_2=2r\\\\
I=?\\\\\\[/tex]
[tex]I= \frac{E_e}{r_e}= \frac{E_1r_2+E_2r_1}{r_1r_2}\\
I= \frac{2Er+2Er}{2r^2} = \frac{4Er}{2r^2}= \frac{2E}{r} =2E*r^{-1}[/tex]
Raspuns corect: c)