Checking Ohm’s law and the rheostat
Answers are for parents and teachers.
1
In a table U = 2 V gives I = 0.4 A. What is R in ohms?
5
2
Three measurements: 9.8 Ω, 10.1 Ω, 10.1 Ω. Their average?
10
3
The working part of a rheostat is 30 Ω and the source is 3 V. The current in mA?
100
4
Describe in your own words the structure and working principle of a rheostat.
It has wound wire and a slider; the slider changes the length of wire carrying current, hence the resistance.
5
Why are wires disconnected only after the key is opened?
Disconnecting with no current is safe and avoids sparks and overheating.