- #1
latentcorpse
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another pretty simple question that i can't see:
a 1d harmonic oscillator of mass m carries an electric charge q. a weak uniform, static electric field of magnitude E is applied in the x direction. what is the classical electrostatic potential energy for a point particle at position x.
ans: W=-qEx
i said [itex]W=\frac{1}{4 \pi \epsilon_0} \frac{q q_p}{x}[/itex] where [itex]q_p[/itex] is the point particle.
now [itex]E=\frac{1}{4 \pi \epsilon_0} \frac{q_p}{x^2} \Rightarrow W=qEx[/itex]
i have two questions,
(i) why am i missing a negative sign?
(ii)was i correct to use [itex]q_p[/itex] is my expression for E? surely if [itex]q_p[/itex] is located at x and i have taken E to be the electric field at x then there's a problem there, unless both charges were just meant to be taken as q?
a 1d harmonic oscillator of mass m carries an electric charge q. a weak uniform, static electric field of magnitude E is applied in the x direction. what is the classical electrostatic potential energy for a point particle at position x.
ans: W=-qEx
i said [itex]W=\frac{1}{4 \pi \epsilon_0} \frac{q q_p}{x}[/itex] where [itex]q_p[/itex] is the point particle.
now [itex]E=\frac{1}{4 \pi \epsilon_0} \frac{q_p}{x^2} \Rightarrow W=qEx[/itex]
i have two questions,
(i) why am i missing a negative sign?
(ii)was i correct to use [itex]q_p[/itex] is my expression for E? surely if [itex]q_p[/itex] is located at x and i have taken E to be the electric field at x then there's a problem there, unless both charges were just meant to be taken as q?