Simple Electric Potential/Field problem

  • Thread starter Thread starter Defennder
  • Start date Start date
  • Tags Tags
    Electric
AI Thread Summary
The discussion revolves around a first-year physics question regarding the electric potential and field at the location of a point charge. The original poster is uncertain whether to take limits as the distance approaches zero, leading to confusion about whether the values become infinite or undefined. Responses clarify that the electric potential at the location of the point charge is indeed undefined. The conversation highlights the common misunderstanding of electric fields and potentials in relation to point charges. Overall, the consensus is that the electric potential and field at the point charge itself cannot be defined.
Defennder
Homework Helper
Messages
2,590
Reaction score
5

Homework Statement


Okay this is a simple first year physics question, but I couldn't find anything about it online. Using the simple equation for electric field/potential due to a point charge, what's the electric potential/field at the coordinates of the point charge itself?


Homework Equations





The Attempt at a Solution



I'm tempted take limits as r approaches 0, but that seems to imply it approaches infinity which appears absurd. Either that or it's undefined. Anyone?
 
Last edited:
Physics news on Phys.org
its undefined.
 
supratim1 said:
its undefined.
You're two years too late. :smile:
 
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}...
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...
Back
Top