What Do p and l Represent in the Resistance Formula R = pl/A?

  • Thread starter Thread starter anzgurl
  • Start date Start date
AI Thread Summary
In the resistance formula R = pl/A, "p" represents the resistivity of a material measured in ohm-centimeters, while "l" denotes the length of the material. Each material has a specific resistivity value. When using the formula, if the length "l" is given in kilometers, it should be converted to meters for consistency with the units used for resistivity. The equation maintains dimensional consistency, ensuring that resistance is calculated correctly in ohms. Understanding these variables is crucial for accurate electrical calculations.
anzgurl
Messages
8
Reaction score
0
R= pl/A
what does p and l stands for?
 
Physics news on Phys.org
p is the resistivity of a material(ohms.cm). Every material normally has a set value for it. l is the length of the material.
 
thank you
But if i had a distance of 100 km ,do i replace "l" with d and convert it to metres?
 
from my experience with this equation(electronic subject) we had "l" in cm, but that was because we had "p" in ohm.cm for example

R = pl/A ----> ohms = [(ohms.cm)(cm)]/cm(^2)
 

Thread 'Struggling to understand the concept of this question (ice cube in water optics question)'

TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
View full post »
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
View full post »

Similar threads

Resistivity equation relating to equations for resistors
Replies
23
Views
2K
Resonant frequency of L - R||C circuit
Replies
21
Views
1K
Resistivity of a wire that is wound close on a cylinder
Replies
2
Views
1K
Resistance of a Copper Wire with initial and final radius
Replies
8
Views
3K
Can I integrate to find resistance of an object of increasing radius?
Replies
7
Views
2K
Difference between two formulas of resistance
Replies
15
Views
3K
How can one derive an expression for \( w^2 / k \) using \( b, p, l \) only?
Replies
3
Views
1K
Calculating Resistance in a Hollow Cylinder with a Pierced Hole
Replies
1
Views
4K
Net force between two conducting strips
Replies
6
Views
847
Lab: Plot graph of resistance, R (in Ohms) versus 1/d^2
Replies
21
Views
11K

Hot Threads

Recent Insights

Back
Top