Readings for two conductors: A resistor: I = 0.1, 0.2, 0.3, 0.4 A with V = 0.8, 1.6, 2.4, 3.2 V…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
Readings for two conductors:
- A resistor: with .
- A bulb: with .
Find for each reading. Which one obeys Ohm's law?
Need a reminder? The key ideaShow
Ohm's law: at a steady temperature, . So and , with in ohms (). The V-I graph of such a conductor is a straight line through the origin; its slope is .
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. The resistor. , and every reading gives .
Step 2. The bulb. , , then : the ratio grows.
Answer: the resistor obeys Ohm's law, with . The bulb does not: its resistance rises as it heats up.
Check. The resistor's V-I graph is a straight line; the bulb's curves upward.
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