| 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.
Tip: Move results to the (I, U) coordinate system, $U=E-R_{s}I$
Answer: The emf of the unloaded battery is 1,48 V and short-circuit current is 3,67 A
