Potential difference Definition and 688 Threads

Hey there! Having some difficulty with this question... is there any proportionality law between potential difference and velocity? An electric charge accelerated from rest through a potential difference of 250 V reaches a speed of 9.4
x 10^6 m/s. What speed will this same charge reach...

Homework Statement 10. If an electron is released from infinity, how fast will it be traveling after falling to within 10-8m of a charge q of 4.8*10-19? a. 1.32*104m/sec b. 8.7*104m/sec *c. 2.76*105m/sec d. 4.01*105m/sec Homework Equations ΔU=ΔVq V=kq/r conservation...

Homework Statement See attached image. I'm having trouble applying the concept of potential difference in a circuit. Vb-Va=? Va-Vb=? Homework Equations Vab=Vb-Va The Attempt at a Solution The overall voltage is 5V-2V=3V. The direction of the current is defined by the higher voltage...

Homework Statement The work done by an external force to move a -8.5μC charge from point A to point b is 15x10^-4 J. If the charge was started from rest and had 4.82x10^-4 J of kinetic energy when it reached point b, what must be the potential difference between a and b Homework Equations...

Determine how far apart two parallel plates must be situated so that a potential difference of 2.50*10^2 V produces an electric field strength of 2.00*10^3 N/C F=(k*Q1*Q2)/r^2 PD=kQ/r E=kQ/r^2 I cannot even figure out which formulae to combine...

Homework Statement I have this circuit here.. http://s1167.photobucket.com/albums/q639/jay9313/?action=view&current=EM.jpg The question says that when switch S is open in the circuit shown above, the potential difference between points a and b would be.. A) 0V B) 6V C) 12V D) 24V E) 36V...

I learned Potential but could not understand what Potential Difference is. Some define it as Work Done per unit charge. I am confused what per unit charge is. Does that mean electrons or protons ? As much as I know, electric current is the flow of negatively charged electrons to the positive...

Can someone explain to me what potential difference means? Lets say point A has a potential of 100 V and point B has a potential of 0 V. So V_AB would be 100 - 0 = ΔV But what exactly does that tell us? What does ΔV=100 do ?

Homework Statement true false Work done by external forces in moving a unit positive charge from A at potential Va to B at potential Vb is Vb-Va Homework Equations basic electrostatics. The Attempt at a Solution dW -F.dr=-Dw if a unit charge move from Va to Vb then change in...

Ignore this. How does one delete a post?

hi everyone, i would like to ask some quick questions that i find confusing. first, electromotive force is the energy supplied by a battery / power source, to ''push'' the charge through a circuit right? its unit is in Volts. then, potential difference is defined as the work done to push 1...

Homework Statement The potential difference between the ends of a 2 meter stick that is parallel to a uniform electric field is 400V. The magnitude of the electric field is: Homework Equations V = E.d The Attempt at a Solution E = v/d = 200 v/m The right answer is 800 v/m, my...

Hi, this problem is from 'Electromagnetism' by Grant & Phillips and it states, Homework Statement 'http://i1129.photobucket.com/albums/m505/physicsbird1/126fig.png" shows a cross-section of the cylindrical high-voltage terminal of a van der Graaff generator, surrounded by an 'intershield'...

Homework Statement A top half of a spherical shell has radius R and uniform charge density sigma. Find the potential difference V(b)-V(a) between point b at the north pole, and point a at the center of the sphere. Homework Equations The Attempt at a Solution \oint E ds =...

The dipole moment of a water molecule is 6.2 x 10-30 Cm. Find the potential difference VB - VA between 2 points on the axis of the molecular dipole, where points A and B are 8.2 nm and 5.1 nm respectively from the center. Both points are closer to the positive end. I used the superposition...

My professor said to in order to solve this, integrate the electric field to find the electric potential... \Delta V = -\int\stackrel{\rightarrow}{E}dl My question is, using Gauss's Law, (\oint E_{n}dA = \frac{Q}{\epsilon}), how do I go about finding Q? Isn't Q just the charge of the shell?

Homework Statement a) What is the energy of a photon that has a wavelength of 0.10 μm? b) Through approximately what potential difference must electrons be accelerated so that they will exhibit wave nature in passing through an aperture 0.10 μm in diameter? The Attempt at a Solution I've...

Homework Statement Calculate the charge on and the potential difference across each capacitor Homework Equations C|| = C1+C2+C3... C(Series) [(1/C1)+(1/C2)+(1/C3)+...]^{-1} Q=CV V=Q/C The Attempt at a Solution I already know that C_{123} = 16/9 \muF I also already know that...

Homework Statement Assume we have cavity in conductor. In the cavity we have +3q charge and conductor charge is distributed uniformly and is +7q. With Gaus law we now that E=0 inside the conductor becaus Q enclosed is 0. But I have been wondering is there potential difference from inner...

the work done to move 4 C of change from a point to another point in an electrical field is 100J.What is the potential difference between the two points?

Homework Statement Two capacitors, C1 = 20 micro Farads and C2 = 5 Micro Farads are connected in parallel and the resulting combination is connected to a 12-V battery. Find (a) the Equivalent capacitance of the combination, (b) the electric charge on each capacitor, (c) the potential...

Homework Statement A square circuit with side L lies in the x-y plane, is centred on the origin and has sides parallel to the x and y axes. At time t=0 it starts turning about the x axis, in a region characterised by a uniform magnetic field B parallel to z, with uniform angular speed omega...

Homework Statement Find potential difference Vab between points a and b on the figure. All resistances and emf’s are indicated, note the polarity of the batteries. What happens if the polarity of E1 is reversed (polarity of E2 kept the same) and both emfs are made equal? Homework Equations...

R1 = 120ohms R2 = 820ohms R3 = 2200ohms E1 = 15v E2 = 9v What is the potential difference between points "B" and "C"? (I've attached the circuit diagram)

Homework Statement A rod rotates clockwise about a point as pivot with the constant frequency 5 rev/s. Find the potential difference between its two ends, which are 80 cm apart, due to the magnetic field B = 0.3T directed into the page. Homework Equations There are two methods to find...

Homework Statement "Two 2.1cm x 2.1cm plates that form a parallel-plate capacitor are charged to +- 0.705 nC. What is the potential difference across the capacitor if the spacing between the plates is 1.20mm? " Homework Equations C = Q/V C = epsilon * A/d The Attempt at a Solution I...

The potential difference necessary to accelerate an He+ ion...? Homework Statement "What potential difference is needed to accelerate a He+ ion (charge +e, mass 4u) from rest to a speed of 1.2×10^6 m/s?" Homework Equations K_f + q*V_f = K_i + q*V_iThe Attempt at a Solution I figure that...

I've heard about this over and over again, but i don't how this(negative pd) can be achieved in an electric circuit.

Homework Statement The problem is to find out the potential difference between P and Q in the following figure- The solution given takes the charges on two capacitors to be equal. Why is it so?

Homework Statement In my book, it says the following http://img849.imageshack.us/img849/388/unledpx.th.png Uploaded with ImageShack.us If you go from a to b, you gain potential. Now here is my question: I thought the E-field points from + to - in that cell, so if the current is...

Homework Statement I am trying to get the velocity of an electron which has been accelerated through a potential difference of 1x106 V, so that i can find its momentum.Homework Equations K=(1/2)mv2 v=sqrt(2K/m) The Attempt at a Solution So , K = 1x106eV and m = 0.511x106eV/c2...

I have a circuit that is in a read only file so I can't get an image on here so I will try to create it on here B-battery C-capacitor ----C1------------- l.....l...l B...C2...C3 l.....l...l -------------------- Ignore the periods (.) because they are just place holders. The...

Homework Statement Consider the circuit shown in the Figure, where R1 = 29 and R2 = 4.8 . http://www.webassign.net/walker/21-44alt.gif (a) Is the current flowing through the battery immediately after the switch is closed greater than, less than, or the same as the current flowing...

Homework Statement Given a point charge of 500pC at the origin, find the potential difference between points a and b at distances 5m and 15m respectively along the x-axis. Homework Equations Coulomb's law, I think? The Attempt at a Solution The reason I thought coulombs law was relevant...

Homework Statement A typical AAA battery has stored energy of about 3400 J. (Battery capacity is typically listed as 625 mA h, meaning that much charge can be delivered at approximately 1.5 V.) Suppose you want to build a parallel plate capacitor to store this amount of energy, using a plate...

Homework Statement For the circuit shown in the figure, find the current through and the potential difference across each resistor. http://session.masteringphysics.com/problemAsset/1169464/1/jfk.Figure.23.P60.jpg Homework Equations V=I(amps)/R(ohms) and Req=R1+R2+R3... The...

Hi I have a question about part a). Using Kirchoff's rules, I got the expression for the charge on the capacitor during the charging phase. q\, = \, 6C \left [ 1- exp ( - \frac{5t}{12C})\right ] and as t goes to infinity, we see that q = 6C so the potential difference...

Very simple question, but is it wrong to believe that current always points in the direction of decreasing potential difference?

We worked out this problem in class and I'm still confused: A wire of resistance 5 ohms is connected to a battery whose emf is 2.0 V and whose internal resistance is 1 ohm. In 120 seconds, how much energy is (a) transferred from chemical form in the battery, (b) dissipated as thermal energy in...

Homework Statement See attached image. Homework Equations Potential difference over a line: V=\int E dl The Attempt at a Solution I assume that the approach to take would be to divide up the problem into different parts, and simply add them together. \int E dl I am a bit...

Homework Statement 2 points x and y, are along orthogonal directions from a 60uc charge. For x and y determine the potential difference between them. ( its in a vacuum also ) x= 10cm, y = 15cm Homework Equations okay, i know the equation is q/4*pi * EoEr *(1/ry - 1/rx) what i don't...

Homework Statement A parallel plate capacitor of capacitance 5.2 µF has the space between the plates filled with a slab of glass with κ = 4.0. The capacitor is charged by attaching it to a 1.8-V battery. After the capacitor is disconnected from the battery, the dielectric slab is removed...

I'm attempting to derive speed in terms of potential difference (voltage), can anyone let me know if there are any errors? http://www.texify.com/img/%5CLARGE%5C%21E_k%3D%5Cfrac%7B1%7D%7B2%7D%5Ctext%7Bmv%7D%5E2.gif...

Homework Statement What is the voltage at D ? What is the the potential difference between B and E? The Attempt at a Solution The point D is connected to +6V and -3 V . So the effecting voltage at D is 3 V. But the answer is -3 V. For calculating the potential difference, I...

Homework Statement I realize I actually don't understand the concept of a battery (potential difference) and a capacitor. From what I know a battery is something that provides a "drive" for electrons. In other words, take a 90V battery for instance, that just means 90J/C, which means it...

An electron is accelerated from rest through a potential difference 1200 V. Give the electron's kinetic energy after this acceleration in electron-volts? ----I know the answer is 1200 eV but if someone could explain how to get the answer?? And how do I apply 1/2mv^2=qV

Homework Statement The capacitors in the figure are initially uncharged and are connected as in the diagram (attached). Then switch S1 closed and switch S2 is left open. After a long wait, what is the magnitude of the potential difference V_{cd}? Answer in units of V. Homework Equations C =...

Hello out there! I am having trouble figuring out how to set this up: A helium nucleus (charge +2e) moves through a potential difference V = −0.70 kV. Its initial kinetic energy is 3.80 10-16 J. What is its final kinetic energy? I feel like I should be using 1/2 mv^2=qV or E=qv. I feel...

Homework Statement A current of 1.82A flows through a copper wire 1.75m long and 1.10mm in diameter. a)find the potential difference between the ends of the wire b) what diameter of copper wire is needed to be a potential difference of .100V Homework Equations I know the resistivity of...

Homework Statement What electric potential difference is required to accelerate and electron, initially at rest, to the speed at which it will move in a circular path with radius 1cm when the electron enters a region of uniform magnetic field of 1.0T, if the field is perpendicular to the...