| Difficulty | Secondary School | High school/other |
| ★ | Basic | Easy |
| ★★ | Demanding | Basic |
| ★★★ | Demanding | |
| ★★★★ | Difficult | |
| ★★★★★ | Very difficult |
Determine the electromotive force (emf) of the unloaded battery and short-circuit current.
Move results to the (I, U) -coordinate system, $U=E-R_{s}I$
Answer: $E=1,58 V$
$I_{short-circuit}=6,28 A$
$I_{short-circuit}=6,28 A$