| Difficulty | Secondary School | High school/other |
| ★ | Basic | Easy |
| ★★ | Demanding | Basic |
| ★★★ | Demanding | |
| ★★★★ | Difficult | |
| ★★★★★ | Very difficult |
Define the resistance of a component.
Tip: Measure voltage and electric current. Move the data (I, U) -coordinate system. What do you find out?
Answer: $210\ \Omega$