| Difficulty | Secondary School | High school/other |
| ★ | Basic | Easy |
| ★★ | Demanding | Basic |
| ★★★ | Demanding | |
| ★★★★ | Difficult | |
| ★★★★★ | Very difficult |
Specify the power of one lamp as well as the power of the lamps. Both lamps are similar.
Answer: Power of the lamps is 0,90 W; the power of one lamp is 0,45 W