Electric Definition and 1000 Threads

  1. D

    Electric field in the narrow wire

    i've started from this I1=I2 then I1= JA1=##\frac {E l} R## I2= JA2=##\frac {E_2 l} R## but can't get anything useful relating them. Am i forgetting any other useful formula? I get as result E4
  2. A

    Electric Field for the circular path of a positively charged particle

    Here is picture. Answers is A. My attempt was that I thought if i were to place a positive test charge then it would go from top to bottom if there was a positive charge in the center it was avoiding and a positively charged particle at the top, but an electron at the bottom so it would avoid...
  3. J

    Electric mining truck creates electric power

    A fully electric mining truck has been built that does not burn fuel. It has a 600 kilowatt-hour battery pack, and they need to discharge about 200 KwH of that every night to keep from overcharging it. The secret: It's loaded at the top of the hill, and unloaded at the bottom. The regenerated...
  4. C

    Is the Electric Field Calculation Consistent with the Potential Result?

    Question Part C Part D
  5. C

    Proving limits of electric fields on infinite planes

    rt a)
  6. C

    Deriving an Expression for an Electric Field along the Z axis

  7. E

    Does electric potential exist without a test charge?

    Usually for a charge Q we state that for each point in space there exists a potential, and we can calculate this, draw graphs of potential etc. However, if electric potential energy is a property of a system of two charges, and potential is PE for a 1C test charge, then how can we even define a...
  8. Yalanhar

    Electric Field due a charged disk

    Homework Statement: uniformly charged disk, radius r, with surface charge density ##\sigma## . I want to find the electric field along the axis through the centre of the disk at a h distance Homework Equations: ##dE=\frac {kdq}{r^2}## My Solution: ##dE=\frac {kdq}{r^2}## in this case r=s...
  9. Yalanhar

    Calculate the electric field due to a line of charge of finite length

    Homework Statement: A thin rod of length L and charge Q is uniformly charged, so it has a linear charge density ##\lambda =q/l## Find the electric field at point where is an arbitrarily positioned point. Homework Equations: ##dE=\frac{Kdq}{r^2}## A thin rod of length L and charge Q is...
  10. AndresPB

    Electric Field from its Potential of a Half Circle along its Z axis

    So I figured out the potential is: dV = (1/(4*Pi*Epsilon_0))*[λ dl/sqrt(z^2+a^2)] . From that expression: We can figure out that since its half a ring we have to integrate from 0 to pi*a, so we would get: V = (1/(4*Pi*Epsilon_0))*[λ {pi*a]/sqrt(z^2+a^2)] In that expression: a = sqrt(x^2+y^2)...
  11. N

    Find the Electric Field E using Gauss' Law

    I tried to work out both a) and b), but I am not sure if I am correct. I drew a picture with a sphere around q first with radius r and then with radius 3r. For a) ##E.A=\frac {q}{ε_°}## (when using Gauss' Law) Since ##A=4πr^2##, I substituted this in the equation and solved for E giving me...
  12. adamaero

    Understanding Electric Force on Q in Relation to Distance d and Charge Q1

    x^2 + d^2/4 = d^2 x = sqrt(3d^2/4) F_1x = sqrt(3)*d*k*Q1/2. In the solution, where did the "d" in the numerator go?? Is my math wrong?
  13. T

    I Electric dipole moment of the nucleus of an atom

    Summary: Why is the electric dipole moment of the nucleus of an atom equal zero? Summary: Why is the electric dipole moment of the nucleus of an atom equal zero? I read about the hyperfine interactions that cause the altering of the energy levels of the nuclues of an atom. Under the...
  14. adamaero

    By using Gauss' law, can the electric field be p/(pi*ε*r^2)

    Which is better to use? The equation for the area or the circumference of a circle? Schaum's Electromagnetics (4 ed) by Edminister vs http://hyperphysics.phy-astr.gsu.edu/hbase/electric/elecyl.html
  15. S

    Electric field due to two positive charges

    I am having trouble solving the following problem. I am given two positive charges on the x axis: I know that the electric field strength at point P is ##E=150 \frac{V}{m}##, ##d=1.8m## and ##a=2.5m##. I want to find the charge of ##Q##. As far as I know, the electric field on the y-axis...
  16. R

    Electric field on a ring's axis

    The contribution coming from a little segment of the ring is ##d\vec{E}=\frac{dQ}{r^2}cos\theta \hat{z}##, assuming that the horizontal components cancel out. But how can we show that?
  17. navneet9431

    Would electric field exist if there were only one type of charge?

    I believe the answer is incorrect, reasons: The answer assumes that electric field will exist . But this is not the case , until and unless there is a bipolarity there cannot be an electric field ( in case of isolated charged objects, the field exists because the bipolarity is separated by a...
  18. Zahid Iftikhar

    Electric Field of a moving charge

    When a charge is at rest, it has an electric field only. When the charge starts moving , it is said to have accompanied a magnetic field. My question relates to its electric field while in motion. Does it still exist or not? I know in electron guns electrons are deflected while passing thru the...
  19. S

    How to measure electric and magnetic fields in asymmetric capacitors?

    Summary: I need to build an asymmetric capacitor, but the mathematics of electromagnetics become too tough, do you have any info that can help? Appreciate it! Hello, I am an undergraduate student in engineering and I want to build an asymmetric capacitor, so I need electromagnetics which I...
  20. J

    Electric Field for Charge Distributions

    We are given: q1 = +2.0 x 10-5 C, q2 = q3 = -3.0 x 10-5 C, r31 = r21 = 2 m a) We start by finding the electric force between q3 to q1 and q2 to q1 FE31 = k * q1 * q3 / r312 FE31 = (9.0 x 109 Nm2/C2) * (+2.0 x 10-5 C) * (3.0 x 10-5 C) / (2 m)2 FE31 = 1.35 N FE21 = k * q1 * q2 / r212 Since...
  21. P

    Calculating a Non-Uniform Electric Field Given 6 different Electrode Pairs

    I know how to find the electric field of more traditional designs i.e. a sphere, through Gauss' Law but I don't think Gauss' Law applies to this scenario. I tried to separate each part of the electrode into simple spheres and rods and using Gauss' Law to find these individual elements. This...
  22. K

    Electric Circuts (Voltage, Ohms, Amps)

    I made a chart and this is my attempt. I am not sure that I am doing the calculations right thou
  23. merlyn

    The phase of electric and magnetic forces in a photon.

    I'm curious if someone help me understand why the electric and magnetic forces are IN PHASE at right angles to one another? Should they not be 90 degrees out of phase in order to conserve energy? I do understand they are in phase but why? Thank you all for your time. Merlyn.
  24. C

    Small doubt regarding electric charge

    Good morning I'm no expert in classical physics, so I have one doubt. If I have a body with mass M, and I charge it electrically with x C (Coulombs), will its mass remain the same, or will it change (in which amount)? Can you help me in the case of a ball, let's say, with 1.5 Kg charged with...
  25. Anand Sivaram

    Question About Electric Aircraft Propulsion

    I have been thinking about this subject for some time now, based on the following considerations 1) Many companies are working on Electric Aircraft Propulsion, high energy density Li-Ion batteries are used to power Electric motors and they drive propellers. This is the approach every one is...
  26. C

    The source of the electric field of a battery?

    If you place a zinc / copper battery it will create an electric field pointing from the copper to the zinc and my question is this what makes this electric field , the zinc pushes electrons in the circuit and never "stays" negatively charged for an electric field to be created same for the...
  27. S

    Find the charge of a mass hanging from a pendulum in an electric field

    Hi, so I was able to solve this problem by just equating the forces (Tension, mg, and EQ). But I thought I could also solve this problem with Conservation of Energy. However, I calculated it several times, and I never get the right answer this way. Doesn't the Electric Field do the work to put...
  28. Physics lover

    Variation of electric field and potential along the axis of a cone

    Options are at the top of page as a) b) c) d) Answer may more than one. Now since 'a' is distance from the smaller surface of cone so as we move along the axis area will increase,So current charge density will decrease and as we know J=sigma E,E will decrease,but V will remain constant since...
  29. M

    Electric field in a circuit with a DC source

    So I understand that when an electric field is produced in a conductor of length L, the net electric field in the conductor will be 0 because the rearrangement of electrons in the conductor results in the production of its own electric field which cancels out the one produced initially...
  30. T

    Solving for Electric Field at an Angle: Ex = 10.0V/m

    Ex =10.0Vm-1 dx= d2=x2+y2 x=4.00m y=3.00m d2=4.002+3.002 d=5.00m Ex = -dV/dx 10.0Vm-1=-dV/5.00m 10.0Vm-1*5.00m=-dV -50.0V=dV So from origin at 100V-50.0V = 50.0V But the solution I am given gives the answer at 50.5V and the information "directed at 45.0◦ " does not seem to have been used so may...
  31. N

    Could Radioisotope Thermoelectric generators power electric cars?

    Could electric cars be given longer range by radioisotope thermoelectric generators like they use to power spacecraft in deep space?
  32. Pushoam

    The electric field inside and outside of a dielectric

    I bring a dielectric in a region with electric field ##\vec E_0##. Net electric field ## \vec E_{net} = \vec E_0 + \vec E_p ## , where ## \vec E_p ## is electric field due to polarization of dielectric. For linear dielectric, ## \vec E_p ## is 0 outside the dielectric. So, ## \vec E_{net} =...
  33. Z

    B Why are there only two types of electric charge?

    Why are there only two types of electric charge? I'm asking as a total layman in science. I've started to wonder about this the more I watch popular science videos about the Standard Model of particles physics and about matter and antimatter. In particular, the various types of subatomic...
  34. A

    How to stop a steering wheel using an electric motor?

    Problem Statement: i have a steering wheel mounted on an electric motor, and i want to stop the driver from going beyond a certain angle. i can read the torque applied by the driver, and the steering wheel angular velocity as well. how can i stop the steering wheel, without sending it harshely...
  35. H

    Strange question about cancelling electric fields

    I am curious about the case where two electric or magnetic fields cancel each other out (I'm assuming this is possible). If a charged particle travels through the region where the cancellation exists, I am assuming the particle behaves as if no field exists. Does that area still have electric...
  36. H

    Do electric fields have their own separate inherent charge?

    I am assuming the answer is NO. I realize that the electric field of any charged object has an energy density, but I was curious to know it that same field has it's own 'charge density' so to speak, and that it would have a small secondary electric field of it's own. This would imply that...
  37. E

    Draw an electric circuit potential graph

    Hi. I have physics homework that I don't understand. Hopefully, someone here can give me some advice. So, the homework goes like this: Draw an electric circuit potential graph and find out the potential difference between points B and C. The two resistors have equal values. Believe me or...
  38. H

    Energy Density of Electric Fields: Is it the Sum of All Electrons?

    I understand that the energy of an electric field arises from the work put into gathering the electrons together to create the field. Bringing electrons close together requires energy because they naturally want to repel. This potential energy is stored in the field itself and the field has an...
  39. DaTario

    Electric current being alternated with continuous part

    Summary: In which scenario a current may exhibit alternated and continuous character together? Hi All, I would like to know in which scenario an electric current may exhibit alternated and continuous character? Something like $$ I(t) = I_0 \sin (\omega t) + I_1 $$.
  40. alexmahone

    Average electric field over a spherical surface

    I'm sure the average is going to be an integral, but \displaystyle\frac{1}{4\pi R^2}\oint\mathbf{E}\cdot d\mathbf{a} gives me a scalar, not a vector.
  41. M

    Finding the maximum value of the electric field

    I tried to find it the following way but to no avail: Let maximum value of ##\sigma## be ##S## Now unfortunately, we do not have a maximum value for ##\dfrac{1}{r^2}## because the field point can be as close as we want to the arbitrary surface charge. (The field at a point on the surface is...
  42. dRic2

    Simple electric potential and Laplace equation

    Imagine to be in 2 dimensions and you have to find the potential generated by 4 point-charges of equal charge located at the four corners of a square. To do that I think we simply add all the contributions of each single charge: $$V_i(x, y) = - \frac k {| \mathbf r - \mathbf r_i|}$$ $$ V(x, y)...
  43. fight_club_alum

    Particle that moves in an electric and magnetic field

    m = 0.005 q = -70 x 10^-6 c v = 30,000 m/s Since there is no movement vertically Fb = Mg So, q . V . B = mg So, (70 x `10^-6) . (30,000) . B = (0.005) . (9.8) So, B = 0.0233333 or ~ 23 MT
  44. J

    Why don't electric motors use exciter coils like generators do?

    I remember (long ago, in college physics) learning about electric motors and generators, specifically about the "exciter" coils in generators which did a better job than permanent magnets, because of a sort of "turbo" or force-multiplier effect. I notice, however, that while basically ALL...
  45. C

    Why Does a Static Electric Discharge Make a Sound and Light?

    Since electrical charges causes a sparkle or a crackle which is light and sound. Also light and sound are forms of energy does that mean that electrical discharge releases energy and if yes then the release of energy have an effect on charge
  46. K

    Clarification of electric potential difference

    I have some questions regarding the sign of potential difference. For example, given the literal definition as the difference in potential between two locations it should be possible for potential difference to be negative if the final potential is less than the initial, but while reading texts...
  47. Kasiopea

    Why is the x-component of the electric field at point P positive?

    I got the answer: E(P)=(k*Q)/(3î )−(k*Q*ĵ) /2 Can someone confirm if this is the right answer?
  48. jmemo

    Find the direction and magnitude of an electric field

    Find the direction and magnitude of an electric field that exerts a 4.65 ✕ 10−17 N westward force on an electron. (Enter the magnitude in N/C.)
  49. R

    Divergence of an Electric Field due to an ideal dipole

    Given $$\vec E = -\nabla \phi$$ there $$\vec d \rightarrow 0, \phi(\vec r) = \frac {\vec p \cdot \vec r} {r^3}$$ and ##\vec p## is the dipole moment defined as $$\vec p = q\vec d$$ It's quite trivial to show that ##\nabla \times \vec E = \nabla \times (-\nabla \phi) = 0##. However, I want to...
  50. somasimple

    Ion migration by diffusion in an electric field

    Hi, A solution contains some ions (charged particles). We are only interested in my exemple to positive ions. It is assumed that these ions acquired some mobility under a concentration gradient. Their direction is A to B. Then these ions encounter/cross an electric field which is oriented from B...
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