- #1
Cici2017
Homework Statement
Homework Equations
The Attempt at a Solution
Can someone tell me what formula to use? Is it p=RA/L? but what about the mass? Thanks~
Resistance of a cylindrical resistor
- Thread starter Cici2017
- Start date
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Homework Help Overview
The discussion revolves around understanding the resistance of a cylindrical resistor, specifically focusing on the relationships between resistivity, dimensions, and mass. Participants are exploring the relevant formulas and the physical principles underlying resistance.
Discussion Character
- Exploratory, Conceptual clarification, Assumption checking
Approaches and Questions Raised
- Some participants inquire about the appropriate formula for calculating resistance, questioning the role of mass in the context of resistivity. Others discuss the implications of volume changes when comparing resistors of different sizes and suggest using physical reasoning over formulas.
Discussion Status
Participants are actively engaging with the problem, offering insights into the physical understanding of resistance rather than solely relying on formulas. There is a recognition of the importance of conceptual clarity, with some guidance provided on the value of thought experiments.
Contextual Notes
There appears to be some confusion regarding the relationship between mass, volume, and resistance, with participants questioning assumptions about the formulas and their applicability in this context.
Can someone tell me what formula to use? Is it p=RA/L? but what about the mass? Thanks~
- #2
Dadface
- 2,489
- 105
What can you infer about the volume of the smaller resistors compared to the volume of the larger resistor?
- #3
Cici2017
p=m/V ,Dadface said:
if m half, V half,
V=πr2L
right?
- #4
epenguin
Science Advisor
- 3,638
- 1,014
Cici2017 said:
I will tell you don't use any formula. It will do you no good, maybe less than none. Use physical thinking. Use a thought experiment like slicing a resistor in two.
Get the physical understanding then that will help you understand the formula!
- #5
Dadface
- 2,489
- 105
I agree with epenguin who has given you very good advice. If you do need to refer to a formula try to get a good understanding of what the formula is actually referring to. In many cases you will find it's common sense. Without understanding the formula you're just substituting numbers and probably learning very little.