# Tagged Questions

The study of the presence and flow of electric charge. Charges, currents, fields, potentials.

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### Can an Oven being set to a different temperature cause electric board to go off?

Basically: the electrical system kept going off (when light goes down in a division due to too many electrical appliances on at a time, or their combined power consumption). My roommate said it was ...
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### tranfser of electrons between two metals and a wire

If you have a circuit of a battery, a Resistance and a light connected with a wire by example: in the middle the wire is cutted in two pieces. if you connect each piece of wire with a metal object and ...
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### How much is a Coulomb, really?

I've heard it said in my physics class that a Coulomb "is a lot of charge". And I believe it; most of the problems I've done in the class so far involve charges on the order of micro-Coulombs (or, ...
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### Drift velocity of electrons in a conductor

How does the drift velocity of electrons in a conductor depend on the temperature? I have two contradicting views for this. First, we can say that increasing the temperature of the conductor will ...
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### Why do we prefer using materials of high resistivity in laboratory instruments?

I know that :$$R=\rho\frac{l}{A}$$ where $R$ is the resistance of the wire, $\rho$ is its specific resistance (resistivity), $l$ is its length, and $A$ is the area of cross-section of the wire. Why ...
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### Doesn't any massive conductor look like “ground” to an AC supply?

I've been puzzling over this excellent answer to the perennial "Why don't I get shocked by a hot wire if I'm not grounded?" question. The orders of magnitude just don't seem right for two reasons: ...
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### How to insulate static electricity

This is a follow up question to Extending the reach of a crocodile clip for Kelvin Water Dropper experiment. We have resolved the issue, but now we have the following cable (in the image) that ...
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### How can the copper wire in an electricity generator provide an infinite number of electrons? [closed]

How can copper wire in an electricity generator produce an infinite number of electrons when the is a finite number orbiting each copper nucleus?
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### What effect does voltage have on electron energy levels? [closed]

Is there any effect at all on an electron's energy level when subjected to a voltage?
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### Are there alternatives to steam in thermal power stations?

'A thermal power station is a power plant in which heat energy is converted to electric power. In most of the world the prime mover is steam driven. Water is heated, turns into steam and spins a steam ...
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### Direction of AC current in a very long wire [closed]

Suppose a wire of length 10^8 meter is connected in the slip rings of an AC generator. Taking the speed of current propagation to be ~10^7 m/s, then it takes 10 seconds for current to flow from one ...
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### How paper strips get electrified?

Why paper strips get electrified when we iron them? I have learned that when two insulators are rubbed then they gets electrified but in case of ironing a paper the iron is a conductor. Will rubbing a ...
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### Why does a battery die more quickly when more resistors are added to the circuit?

I will be explaining what I think: A battery acts like a pump which provides energy to do work on negative charges to move them towards the negative terminal, and hence creating an electric field. ...
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### Why is lightning going from the Earth to the clouds while the electrons are going from the clouds to the Earth?

The lightning is often a discharge in advance. The (negative) charge slide occasionally a little further on in the conductive channel, wherein said channel is highlighted each time something. The ...
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### Why does a higher wattage incandescent light bulb have a lower resistance value than a lower wattage incandescent light bulb

I am an electrician and know through experience that resistance in an electrical circuit causes heat. An incandescent light bulb's light is a by-product of heat, so why does a 100w bulb have a lower ...
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### Measuring Static Electricity

Is it possible to measure the static electricity in a room using a VOM or some other digital meter? I have a lot of static electricity building up in a carpeted room, and would rather not spend the ...
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### What makes Jacob's ladder spark to go upwards?

In a Jacob's ladder (https://www.youtube.com/watch?v=GaC4BnbH1NY&index=3&list=PL_SAbPKia2YMFi-t8z5WFYCd86Plcs1Un) a spark is originated in the bottom and climbs up to the top. I have read in ...
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### what would happen to flowing electrons in a vacuum if they are not giving any exit point?

Lets say theoretically electron flow is captured in a vacuum and not allowed to exit then where would they go? I do not want to know the practical impossibilities of it. And also what would happen if ...
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### Touching one end of a battery

What happens when I touch one end of a battery? Is there any flow of charge from the battery to my body? I know that connecting a battery to both ends of capacitor causes the charge from one plate ...
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### What is the dielectric constant of a pure conductor?

Dielectric constant is the ratio of permittivity of a medium to the permittivity of free space. How to find dielectric constant of a conductor?
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### Explanation of duration of forces due to electrostatic charge

when we use the pen and make the rubbing in it the pen can attractive the paper and after 1 sec. the paper fall down because it loss the earned energy but in this video the balloon still attractive ...
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### Why does compton scattering provide evidence for the particle nature of light?

I understand that compton scattering is modeled as a collision between a photon and an electron, but why does this conclusively prove that light can act as a particle? Why couldn't the same ...
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### How is a variable potential divider able to reduce current/voltage through a component to zero, unlike a variable resistor?

For example, the diagram in my text book shows a filament lamp, in series with a uniform resistive wire, which can have its voltage and current varied by moving the sliding contact, e.g., a ...
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### When heat loss is more than energy generated [closed]

Suppose a electric power station produces 200W of electricity @ 200V. Now instead of stepping it up, it decides to transmit it as 200V to a city 20 km away. The transmission cable has resistance per ...
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### Why does a variable potential divider have the ability to reduce current through a component to zero

For example, the diagram in my text book: shows a filament lamp, in series with a uniform resistive wire, which can have its voltage and current varied by moving the sliding contact, e.g., a ...
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Generally we equate change in potential energy to change in kinetic energy but in case of a charged particle like electron this is inconsistent. Consider a case: An electron(of charge e)from rest is ...
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### Separating Interaction of Heat from Electricity?

I have a rod where electricity of frequencies 1-360 Hz is passed through. It is affected by heat. I am evaluating the energy involved in such a process, contributed by electricity and heat. The ...
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### Effect of Electric charge on balloon [closed]

I recently provided a charge to a (inflated) balloon which popped within seconds of introducing the charge ? Why so?
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### Is the $I^2R$ when a resistive heating element is cool the same as when it's hot?

My system (electric resistance element and water bath) heats up 2 degrees in 20 seconds (0.1 deg/sec) when the resistance element if fully heated. Say I want to raise the temperature 0.1 deg every ...
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### Extending the reach of a crocodile clip for Kelvin Water Dropper experiment

We're doing a physics project that involves a version of the Kelvin Water dropper experiment. Everything is working great, and we have the following system: In the image: two plastic containers (...
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### Can a moving magnetic field create eddy currents in a conductor ?

Moving a magnet in and out of a solenoid makes a current flow in the solenoid. I know that a changing magnetic field induces emf in a conductor but what about a moving magnetic field ? Are eddy ...
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### Photocurrent's dependence on frequency [duplicate]

Sounds like a rookie question, this, but could someone please explain to me why doesn't photocurrent increase when we increase the frequency of the incident radiation? I mean, an increase in frequency ...
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### Why didn't 0.2A at 2V kill me? [closed]

I was recently connecting a circuit together like here: and I had the voltage set at 2V, with a 10Ω resistor. By Ohm's law, there was a current of 0.2A (and was confirmed by my multimeter). I ...
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### How to find the current source Is and the voltage V1 of this circuit schematic? [closed]

I have Vs= 1.5V, R1=1 Ohm, R2 =6 Ohms, I got the equivalent resistance to be 7 Ohms. Then I set equal Req to Vs for 7I=1.5 and got my current source to be 0.214A. Since it is only Vs and Req in the ...
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### Inductance coil with self-inductance and resistance

If a coil has $L$ henry self-inductance, resistance of $R$ ohms and potential deferens of $V$ volts what will be the current through it? In my opinion this case should be considered as resistance and ...
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### electric potential and other potentials

We know that without potential difference no electric current can flow.If two conductors carrying positive and negative charge respectively then the first one will have positive and the rest one will ...
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### Zero or non zero electrical potential energy of the system

Say you have this scenario: and you wanted to find the electric potential energy of the +q charge Now if you were to find the potential energy of +Q and +q system and add that to the potential ...
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### Discharged AA cell

Why does a discharged AA cell fall over when dropped vertically? A new AA cell will not fall over when dropped vertically from distance of 2.0 cm. A discharged AA cell falls over when dropped ...
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### AC electricity. I dont know what happens when thevenergy flows both ways in AC electricity [closed]

I know that electricity in AC flows both ways but I do not know what happens when it flows both ways. Whats the difference
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In the diagram below (ignoring the text), does the $V$ mean that there is some electric field outside of this system which results in a potential difference of $V$ between $a$ and $b$ or does it mean ...
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### electrostatics and current electricity

What is the relationship between a closed and open circuits with electromotive force.electromotive force is the force that keeps charge moving in circuit when a potential difference is created.
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### Why do bulbs dim when we switch on TV?

Why do the bulbs dim for a moment when we switch on equipments like CRT television or water pump?
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### Charging with No Current

This may be a basic question, but I am not sure about the exact reason, so I'm asking this I've noticed quite a few times that when you plug an iPad charger to a socket and then switch it on, then ...
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### why do light bulbs explode when in contact with water?

Is it true that when water pours on a light bulb it will explode? If so does this apply to all light bulbs and how does that happen.
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### Does a capacitor experience a Newtonian reaction when being charged?

Say I have a capacitor that is being charged with a battery. There are two wires, one on the positive and one on negative terminal of the battery which go to a capacitor. During the charging, a ...
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### Equation relating voltage and minimum rpm needed for generating 1V using a magnet around copper wire

I was wondering if there is any equation or law or something that relates the minimum rpm needed when a magnet spins around a copper wire to generate 1 volt? In other words, how fast does the magnet ...
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### Difference between potential difference and electromotive force [duplicate]

What is the difference between potential difference and electromotive force? Potential difference is the work done when 1 Coulomb of charge move one region to another.
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### Is it possible to avoid static electricity? [closed]

Sometimes I touch a car or a door and I feel the static electricity in my hand and it hurts sometimes. I try not to touch anything because I feel like I am going to feel this pain again. Is there a ...