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71 views

How do I calculate the total resistance of this circuit? [on hold]

How do I calculate the total resistance of this circuit? From the data from a site it can be calculated that the total resistance is $\frac{12\ V}{5.14\ A}$ which is $2.33\space \Omega$. But I don't ...
-1
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0answers
12 views

Calculate the power supplied by voltage source [on hold]

Hi for this question (sorry about the picture), if the current source ($2A$) receives $20 W$ of Power, determine the $R$ of the resistor and the power of the voltage source. I sort of know I have to ...
-1
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0answers
18 views
0
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3answers
58 views

If the speed of electron (in space) is increased, will the magnitude of current also increase? [closed]

Electrons are emitted by a hot filament and are accelerated by an electric field, as shown in the figure. The two stops at the left ensure that the electron beam has a uniform cross-section. (a) ...
0
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1answer
146 views

Magnetic field in a capacitor

If in a flat capacitor, formed by two circular armatures of radius $R$, placed at a distance $d$, where $R$ and $d$ are expressed in metres (m), a variable potential difference is applied to the ...
0
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0answers
31 views

Does the potential difference between two points remain the same if there spatial location is changed?

I was working through this particular homework problem. Where I am required to find out the current flowing through the resistor A (4 ohms). First of all I saw that the 2 resistors were in parallel ...
2
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2answers
107 views

Induced Currents in Circuits

I was given the following question:- The plane figures shown are located in a uniform magnetic field directed away from the reader and diminishing. The direction of current induced in the loops is ...
0
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1answer
52 views

Determining current in a branch having no resistor [closed]

In context to the diagram below , it is quite easy to find the current flowing through section AD , which turns out to be 2A , however , I cannot determine the current in any other branches with ...
0
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0answers
35 views

Question about current density

I was looking at past exam papers and found a question that I can't understand. It is basically about current flow but the diagram is really confusing me. The diagram is the following: The question ...
1
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1answer
51 views

Divergence of current density and electric field within a wire

In the following exercise: I concern myself with the validity of my interpretations of (b). Here I am more confident slightly. The divergence of the current density is merely $- d \rho / dt$, so as ...
0
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0answers
22 views

Formula for total current and phase angle in function of given currents and phase angles in the branches of a parallel RLC circuit

Consider this parallel RLC circuit powered by an sinusoidal alternating voltage and two branches, one containing an ohmic resistance $R_1$ and a capacity $C$, the other one containing an ohmic ...
0
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3answers
57 views

Orientation of resistor when connected in a cicuit [closed]

Consider a cuboid shaped resistor. Now Case1: Connect the resistor along is length to a battery. Case2: Connect the resistor along is breadth to a battery. In the two cases the length and cross-...
0
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4answers
126 views

What remains the same: voltage, current or resistance? [closed]

A current 1 ampere passed through a conductor which resistance is 10 ohms, if the current become 2 amperes, then will the resistance of the conductor will remain 10 ohms, and if not, then what is the ...
1
vote
2answers
38 views

Potential in open branch of a parallel circuit with grounding [closed]

If the switch is still open, what will the electric potential at Q be, i.e. negative, positive or zero? Is there a potential difference across the grounded point and point Q, or R3, even though the ...
0
votes
1answer
139 views

Is internal resistance of cell part of the equivalent resistance of the network of resistors?

Do we include the internal resistance of cell while calculating equivalent resistance of network? Take, for instance, the question given. Do we include the 1 ohm internal resistance while calculating ...
-1
votes
2answers
66 views

Why in a DC series Circuit do bulb attached in parallel to highest resistance glow brightest? [closed]

I was performing an experiment in which there were five resistances connected in series and then I connected a bulb with each of the resistance. Each bulb was connected in parallel to each resistance ...
0
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3answers
77 views

Brightness of lamp

Brightness of lamp (power) depends on two factors: Current which flows through the lamp. voltage (p.d) across the lamp. In the figure: When the variable resistance increases, what happens to the ...
-3
votes
1answer
62 views

Calculate the voltage between terminals a and b [closed]

Calculate the voltage between terminals a and b before and after connecting the external resistance R, then calculate absolute and relative difference of these voltages.
2
votes
2answers
409 views

What is the equivalent resistance between $A$ and $B$ in the given circuit? [closed]

Hi, I've been doing some current electricity problems by using Kirchhoff's laws. I've tried applying KVL(Kirchhoff Voltage law) to this circuit, but to no avail. There happens to be too many variables ...
1
vote
1answer
97 views

Can electric potential be discontinuous?

I am studying the following problem, which is 9.11 of "Modern Electrodynamics" by Zangwill. The idea is that you have a wire attached to a perfectly conducting sphere (radius $a$) buried into the ...
1
vote
3answers
707 views

Hardest circuit diagram

I have provided an example of the type of problem I am having issues with. In the given diagram, the resistances and batteries are identical and the batteries do not have internal resistances(for the ...
0
votes
2answers
39 views

Compare the time the power sources in these circuits will last

I am trying to conceptualize the time which a battery will last in a given circuit. Below is an example from which I will explain the questions which I am struggling with : Lets begin by asking this ...
-2
votes
1answer
55 views

Circuit Diagram Problem [closed]

I solved a problem in which I was supposed to find the current over the ammeter. The answer is 12 because the total voltage over the circuit is given as 128 V. However, I do not understand why we don'...
-1
votes
3answers
274 views

How to determine direction of the current in the following circuit? [closed]

What would be the direction of the current on R3? Can there be current moving in both directions?(left and right?)
-1
votes
1answer
26 views

Integrating Ampère's force law to find the force between wires [closed]

I want to find the force between parallel current carrying wires using Ampère's force law. Ampère's force law is given as \begin{align} dF&= \frac{\mu}{4\pi} \frac{I_1dL_2\times(I_2dL_2\times r_{...
3
votes
2answers
97 views

Simple electronic circuit analysis [closed]

I have to find a substitute for this circuit. (The substitution is on the right) The arrows in one circle are perfect voltage sources. The arrows in two circles are perfect current sources. It ...
0
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2answers
53 views

circuit analysis [closed]

I have been struggling with this circuit below since my teacher asked a question about it. The question is: -Is there any current flowing in the wire in the middle? The answer is yes. I tried to ...
0
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3answers
261 views

This question was on my physics test (about basic DC circuits) [closed]

So in the following question: Because the wire has a resistance of near 0, is there no current going through the resistor with the arrow pointing at it. I understand that normally both resistors in ...
1
vote
3answers
60 views

Dependency of temperature acquired by a resistor on power

A nichrome heating element across 230V supply consumes 1.5kW of power and heats up to 750*C. A tungsten bulb across the same supply operates at a much higher temperature of 1600*C in order to emit ...
0
votes
1answer
44 views

What is the ratio of the turns in the transformer when it is impedance-matching?

I study physics on my own. There is a question in my textbook: A transformer may be used to provide maximum power transfer between two AC circuits that have diffirent impedances $Z_{1}$ and $Z_{2}...
-1
votes
1answer
462 views

Why do lightbulbs in parallel stay the same brightness when one is removed [closed]

In my book it reads, "The brightness of C: Increase. (If you remove D) Previously C was receiving only half of the current through the lower branch, now C is receiving all of the current coming out of ...
1
vote
0answers
101 views

Electrical resistivity calculation of a cylindrical material

I have a copper rod, its diameter is 13mm, and its height is 13mm. I want to check its electrical resistivity. I have tools to give this copper a constant current by two points (the two black dots in ...
-3
votes
1answer
867 views

Magnetic field around a coaxial cable : Dealing with thicknesses [closed]

How can we obtain the answer here? How can we deal with the thicknesses here? Thank you!
-1
votes
1answer
33 views

Magnet going upward through a loop, direction of current [closed]

This a question that bothers me from a SAT Physics review book. So in the question, there is a bar magnet with north pole up and south pole down going upwards through a loop of wire and (from my ...
0
votes
2answers
34 views

Will the EM field radius of 10 x 20 Amp wires be smaller than a single 200 Amp wire?

Not sure how the radius is determined but Will 10X20amps wires in one conduit(meaning they are together) EMF radius be smaller than 1X200amps wire? I'm having a real life question on this: I can run ...
-2
votes
1answer
23 views

How to identify the number of nodes and their voltage in this case? [closed]

Voltage at each node is required considering the bottom wire is connected to ground, thus making the voltage zero at the bottom everywhere. Is following nodes correct?
3
votes
3answers
163 views

Charge stored in Series Capacitor = $\frac{Q}{3}$

I was reading a problem in class concerning capacitors of equal capacitance C in class today, and I wanted to ask a question about it. If we consider 3 of these capacitors connected in series: <...
0
votes
1answer
43 views

Force Due To a Single current carrying wire

In class today we were given the situation of a single DC current carrying wire was trying to deflect a compass needle. We were told that the magnetic field of the earth was $5\times10^{-5}T$ and we ...
0
votes
0answers
64 views

In which direction does the current flow if we connect batteries with the same poles?

We bind two batteries with voltage 2V and 1.7V with inner resistance 0.2Ω and 0.1Ω in parallel series in such way that we bind each positive poles and negative poles together. What current runs ...
0
votes
1answer
2k views

A square loop of side length $a$ with current $I$ running through it. What is the magnetic field at a distance $x$ from the center of the square? [closed]

We have a square loop of side length a with current I running through it. What is the magnetic field, B at a distance x from the center of the square? So far, I know that I have to use the magnetic ...
1
vote
2answers
312 views

Does direction of current in Node Voltage method circuit analysis matter?

I am trying to solve the following circuit using the node voltage method, but I'm having issues with figuring out how current is supposed to flow in and out of nodes. I understand that the current ...
0
votes
3answers
243 views

Does a conducting rod moving in a magnetic field itself generate another magnetic field?

A standard problem in elementary EM goes something like this: An infinite straight wire conducts a stationary current $I$. A conducting rod, perpendicular to the wire, moves with constant velocity ...
0
votes
2answers
46 views

Representing electricity as electrons

Just a thought I had, I was wondering if there was a practical way to do this: Electricity is represented in Watts per Hour, and obviously, electricity is the flow of electrons. Is it possible to ...
0
votes
1answer
52 views

The equivalent resistance of the networks shown is [closed]

I solved the by taking resistance at the right side as in series but got ans as 5R/13 but the is 5R/11
-5
votes
1answer
490 views

Electric field due to infinite line of charge [closed]

In my textbook it derives the electric field due to an infinitely long linear charge using a cylindrical Gaussian surface. However, if I take a finite-length linear charge, and draw the same cylinder, ...
0
votes
1answer
3k views

Magnetic field at center of rotating charged sphere

Let $\Sigma$ be a sphere of radius $R$ charged with uniform surface density $\sigma$. Supposing $\Sigma$ rotates with constant angular velocity $\omega$, calculate the magnetic field at the center of ...
1
vote
2answers
1k views

Charge flowing through switch when it is closed [closed]

The problem that I'm having is that the initial charges would have been 300 and 600 microcoulomb on the 3 and 6 microfarad capacitors respectively. But when the switch is closed there's some charge ...
0
votes
2answers
455 views

Why doesn't a bird on an electric line get electrocuted? KVPY 2017 [duplicate]

A bird sitting on a single high tension wire does not get electrocuted because A) the circuit is not complete B) the bird feet has an insulating covering. C) capacitance of the bird is ...
0
votes
1answer
66 views

Why does current travel away from the battery's negative terminal in this circuit?

I'm working on physics homework and I wanted to know why the current in this circuit (and some other circuits I see in my homework) moves away from the negative terminal. https://i.imgur.com/7Ld2Gob....
0
votes
1answer
40 views

Is the simplification of this circuit correct?

It doesn't look right to me as the 8 and 4 resistor and the 30 and 17 ohms resistors just disappeared. Can anyone point out the correct way of simplifying the circuit and providing the equivalent ...