New answers tagged

0

You can solve this problem by using Kirchhoff's two laws. Kirchooff's current law tells you that since this is a series circuit the current in each part of the circuit will be the same all the time. So whatever happens to bulb $A$ will also happen to bulb $B$ as they both have the same current flowing through them. Using Kirchhoff's voltage law you have ...


0

You're on the right track. You're probably familiar with how the current decreases exponentially after closing the switch. $$I(t)=I_0 e^{-t/\tau}$$ Where $\tau$ is the time constant of the circuit given by $\tau = RC$, and $R$ is the total resistance of the bulbs. So when the switch is closed, current will be a maximum, and the bulbs brightest. As time ...


2

a. Immediately after the switch is closed, are either or both bulbs glowing? Explain. They will both glow as some current passes through them as the capacitor is charging. b. If both bulbs are glowing, which is brighter? Or are they equally bright? Explain. They are both equally bright, because an equal and opposite charge is flowing on to ...


0

You have to keep this important thing in mind while dealing with problems of these kind. A capacitor behaves as a pure conductor immediately after connecting it with the circuit (i.e., at time t=0). As time passes the capacitor begins to lose its conductance exponentially and finally after a very long time (theoretically when time t tends to infinity) it ...


0

Capacitors affect the flow of electric current in the following ways: Initially when a capacitor is not charged or discharged then, it will allow both A.C. and D.C. current to pass through. But when the capacitor is fully charged, it would restrict the flow of D.C. but would allow the A.C. current to pass through. This effective property of capacitors make ...


1

I would say it is both! Because of the abundance of electrons, the electric field at the battery pole/boundary, at the instant of turning on the switch (t=t0), is quickly (within a few Debye lengths) screened and cannot possibly reach the electrons further down the wire. However, the electrons at the vicinity of the pole that do feel the effect of electric ...


1

I want to charge a 12v 100ah battery which need 20 amp of current. You can charge the battery at any current proving it is not too high and it might be that the 20 amp is the maximum charging current? If the adapter gives a constant (regulated) 12 volts then you will not be able to charge a battery of the lead-acid type it will require more than 12 V ...


0

Batteries are made up of one or more electrochemical cells, arranged in series. In these cells an electrochemical Redox reaction takes place: $R+ze^{-} \to R^{z-}$ $O-ze^{-} \to O^{z+}$ Where $R$ and $O$ resp. are a reducing agent and oxidising agent. This transfer of electrons provides the EMF of the cell. As more current is drawn from the cell, the ...


0

Let $V_{X}$ be the voltage(potential) at X and $V_{J}$ the voltage(potential) at J. The potential at the positive terminal of E is $V_{X}$, the potential at the negative terminal of E is $V_{X}-E$. This is also the potential at the left terminal of r. Since the current through r and the galvanometer is zero, by Ohm's law, the voltage drop across r and the ...


0

It seems to me that, it is not following Kirchhoff second law. In fact, if the voltage $V_{XJ}$ is equal to the emf $E$, Kirchhoff's voltage law (KVL) is satisfied only if the voltage across the internal resistance is zero: $$V_{XJ} = E - V_r,\qquad V_{XJ} = E \Leftrightarrow V_r = 0$$ But this is the case if the cell B current is zero $$V_r = r ...


2

Maybe it is worth bringing a comment into an answer: Batteries have protective circuits. The most basic safety device in a battery is a fuse that opens on high current. Some fuses open permanently and render the battery useless; others are more forgiving and reset. The positive thermal coefficient (PTC) is such a re-settable device that creates high ...


-1

First of all, you should see some properties of a capacitor. A capacitor is a device capable of storing electrical energy. The capacitor can induce an impedance depending on the capacitance of the capacitor and the frequency of input voltage applied. It's called capacitive reactance and is given by: $X_C$ = $1/2πfC $ where f is the frequency of input ...


1

The battery is an energy source that supplies the electrical energy to the electrons in the conductors. There is no actual flow of electrons. It's the energy that is transferred. A conductor contains large no. of atoms tightly packed with plenty of availability of valence electrons that are ready to move out from the atom if you supply a little bit of ...


0

A filament of a light bulb can be thought of as being composed of a lattice of positive metal ions which are vibrating about fixed positions and a sea of mobile electrons which are responsible for the metal being an electrical conductor. With no external circuit present a chemical process within a battery moves mobile electrons within the battery to produce ...


0

I try to think of everything in terms of chemical potential. Many batteries utilize lithium ions to create a chemical gradient. This creates a driving force across the circuit, called voltage. Keep in mind that the electrons are not moving that quickly - it acts more as a wave travelling through. If you are interested, you can learn more about the actual ...


0

Okay, it's partially wrong. A battery is a device that maintains a constant potential difference between its terminals (generally through chemical stuff). Circuits are conductors. Conductors have electrons that can easily flow across their atoms. It's like conductors have a "sea" of electrons. The potential difference causes the circuit's electrons to move ...


0

Use KVL and the potential diagram for $V_1>V_2$ might help you find $V$?


0

Actually the flow of electrons is not that cause the light to glow. The electrons are just carriers of energy. I will make it clear. Consider a bulb connected to a battery. The wire is a conductive metal which means that it is in solid state. So the inter atomic spaces is very less. So the electrons can't move that much freely. There arises a no. of ...


1

Batteries use a type of reaction called a redox reaction that involves the transport of electrons. Rather then the carbon zinc battery, which is a bit complicated consider the simpler example of a zinc copper battery as taught in school science lessons across the world. The reaction is: $$ Zn + Cu^{2+} \rightarrow Zn^{2+} + Cu $$ So the reaction dissolves ...


1

Via a series of chemical reactions a battery sets up a surplus of electrons on the zinc (negative) plate and a deficit of electrons (positive charges) on the carbon (positive) plate because it is energetically favourable to do that. You can think of the reaction as a zinc atom producing a zinc ion and two electrons with the release of energy. Assume that ...



Top 50 recent answers are included