An electronic system, with closed loop current flow, and relative electrical potentials present across electrical components.

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0answers
20 views

PARALLEL COMBINATION OF SUPERCONDUCTORS AND RESISTORS [duplicate]

........................please reply to the question above in the picture. I have tried a lot and have thought about it for a long time. Please help me and answer in simple words. AND I REQUEST NOT ...
2
votes
2answers
50 views

Are these capacitors parallel or in series?

I am a bit confused. The authors say these conductors are parallel when the switch is on. But to me it looks like they are in series since the handle is insulating. How can you explain that they are ...
-1
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0answers
26 views

SUPERCONDUCTORS AND RESISTORS [on hold]

In this circuit 9A current is flowing. The current leaves the battery and reaches junction A (meeting point of resistor of 3 ohm and a superconductor ). So my question is whether all current will ...
1
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0answers
33 views

Determine potential function given initial conditions?

Assuming a radially symmetric circular disk (let's say r=1). Given two simple initial conditions: Potential at the centre is 4 V Potential at the edges is 0 V How would I determine the potential ...
0
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3answers
25 views

Finding equivalent capacitance between A and B, [on hold]

Following is the question, asked is to find equivalent capacitance between A and B. I've tried couple of times and getting 7/3 micro farad as the answer while the correct answer is 8/3 micro farads. ...
1
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1answer
43 views

Bulbs in parallel/series (very basic) [on hold]

I need some help understanding very basic circuit concepts, specifically for the question in the image below. So from what I know is that in a series setup: voltage is divided over the components, ...
3
votes
1answer
119 views

What does a voltmeter actually measure?

For time varying fields (even quasistatic ones) the electric field is given by $${\bf E} = - \nabla \Phi - \frac{\partial {\bf A}}{\partial t}$$ So what does a voltmeter measure? Does it measure a ...
0
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0answers
29 views

Calculate the total impedance of this circuit [on hold]

I'm not very familiar with impedance calculations using complex numbers and I would like to ask for a verification for my reasoning in the the following problem. The problem is to calculate the total ...
0
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0answers
10 views

Charges on outer faces of parallel plate capcitor

Can there be charges on outer charges of a parallel plate capacitor if both the plates are initially charged by different amount and then connected with a battery.
1
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0answers
27 views

Question about notation in a simple circuit [on hold]

I was given this circuit in an Electricity & Magnetism course. On the far left, is that a current source providing 2A? It seems to be but I'm not 100% sure.
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0answers
45 views

Electric Circuit Simplification [on hold]

I have been given a problem to simplify this electric circuit diagram: However, as it's quite unusual for me to see resistors connected in such way I couldn't complete the problem even after ...
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0answers
17 views
-1
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0answers
15 views

Diode Circuit analysis [migrated]

how can i solve circuits like this ?! how current flow though determine the diode modes and calculate V and current in branches
0
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1answer
17 views

Speakers made from two plastic cups, a copper coil, two magnets and some wire: Advice on how to make it louder? [closed]

http://i.stack.imgur.com/ioQTj.jpg http://i.stack.imgur.com/P09CD.jpg Pics above, in side there are two magnets. I have an assignment in my AP Physics 2 class, I need to make speakers that can be ...
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votes
1answer
29 views

E. M. F and potential difference [closed]

Here i =emf/R+r -(eqn.1) . Pd across the cell is equal to potential drop across resistence R. i. e pd =iR . Pd = (emf x R)/R+r -(using eqn. 1) . Also pd =emf -ir . emf -ir =(emf x R)/R+r . Hence ...
0
votes
0answers
17 views

Alternating current in a L-R circuit [closed]

I am having some problem in a numerical. But my answer didn't match. The question is here- An electric bulb is designed to consume 55 W when operated at 110 volts. It is connected to a 220 V, 50 Hz ...
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votes
1answer
20 views

Mechanism by which a capacitor is charged, using surface charges

I want to gain a deeper understanding as to how a capacitor actually gets charged. Consider a situation in which an uncharged parallel plate capacitor is connected to a battery using two wires. I ...
-1
votes
0answers
20 views

Current in a series L-C circuit [closed]

Suppose an inductor-coil, a capacitor and an AC source of rms voltage V are connected in series. Now if the frequency of the source is varied, what is the condition for the maximum rms current in the ...
1
vote
1answer
24 views

Is a real voltaic cell always schematically equivalent to an ideal battery and a resistor?

In the diagram I have attached, the top circuit is the schematic equivalent I am trying to use to model the middle circuit which uses real voltaic cells (that have internal resistance). I am not sure ...
0
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0answers
16 views

BJT transistor as an amplifier [migrated]

I'm confused about a couple of things concerning the transistor.. is Vcc the signal to be amplified or Vin? And does the transistor actually amplify the voltage fed to it or does it just regulate how ...
4
votes
4answers
53 views

Current in inductor just after switch is closed

I have read that the current in an inductor resistor circuit just after closing the switch is zero. This is derived by finding the differential equation in terms of current by using KVL. Is this true ...
0
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1answer
58 views

Can we “use” a capacitor while simultaneously charging it?

I know that capacitors can be charged to work like a battery . But I wanted to know whether we can charge a capacitor while it is in use ( given that the current supplied to it is more than what it ...
-1
votes
2answers
51 views

What is the reasoning behind calculating the resistance between two points on a square resistor circuit? [closed]

Here, the question asks me to work out the resistance between X and Y. The answer is 1.2 ohms. In a normal circuit, the resistance between two points is simply whatever resistor value(s) is between ...
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votes
2answers
65 views

Electrocuted at Parking Pay Station After Snorkeling [closed]

This is my first time posting here so bear with me. Also, the circumstances are strange so I am posting quite a bit of detail because I don't know what is relevant and what is not. The short story is ...
0
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1answer
18 views

Difference between energy loss at high voltage and high current

When reading about power transmission one very common statement is that power is transmitted at high voltage to minimize loss in the form of heat. What confuses me is the governing equation. Aren't ...
4
votes
5answers
148 views

Why aren't resistors equivalent to breaks when $R\to\infty$?

Find the voltage across each resistor as $R\to\infty$ Kirchoff's voltage law gives $$10\ \mathrm{V} - V_R-V_R = 0 \implies V_R = 5\ \mathrm{V}$$ However, don't we get two holes in the ...
0
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1answer
23 views

making sense of measures in electronics

I am in secondary school in the UK, and at this point in physics the information we are given is very vague at a fundamental level. My main concern is with electricity and circuits, and the measures ...
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2answers
24 views

AC circuit having a capacitor

Consider a parallel plate capacitor connected to an AC. The current in the circuit leads the emf by $\pi /2$. My question is, what does it mean that the current lead the emf by $\pi/2$? Does it ...
0
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1answer
20 views

Internal resistance of a cell

I'm a pre-university student, during the lesson of internal resistance r, there's actually resistance in battery or a cell, and if we were to connect it up in a simple set up as below: The situation ...
-1
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0answers
32 views

Why both fuse and earthing ???' [migrated]

This question arose in my mind today that when you already have the fuse for safety precautions why do you need the earthing?
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votes
1answer
46 views

How do I simplify this complex resistor circuit? [closed]

I have this circuit diagram and I need to find the current through the circuit.But I have no idea how to simplify this circuit. I have tried applying Kirchoff's Current Law but could not do it. ...
0
votes
2answers
19 views

Help with electrical current and resistances [closed]

I am working on a physics equation on electrical circuits. I understand it in one direction but I am having issues looking at it backwards. I am given the following: R1 = R2 = R3 = 1.5 Ω Calculate ...
0
votes
1answer
36 views

Resistance from $I$-$V$ graph

I thought that the answer was obviously A as the gradient remains constant...however, the answer is B...who so?
0
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2answers
42 views

Contradiction about cross-sectional area being inversely proportional to resistance

Let us consider a fixed voltage. $ I = nAve $ is the relation between current, number of free electrons in unit volume $(n)$, cross-sectional area $A$ and electron drift velocity $v$. ($e$ is the ...
0
votes
1answer
36 views

Basic circuit problem [closed]

The voltmeter has infinite resistance. What are the readings on the voltmeter when the switch is open and when it is closed? I thought that the reading on the voltmeter would be E/2 ...
0
votes
3answers
35 views

EMF or terminal voltage?

I have a doubt that is: What does this statement mean: "a 6 V battery". Does this mean that the EMF of the battery is 6 V or the terminal voltage of the battery is 6 V? If the battery has internal ...
0
votes
4answers
36 views

Light bulbs in Series

In physics we were learning about how in series the current is the same through each resistor. So that the lightbulbs will all have the same brightness but dimmer than if there was just one bulb on ...
0
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0answers
35 views

RL vs RLC circuit magnetic field

If I want to create an alternating magnetic field using an inductor, what difference would it make to use a series RL or a series RLC circuit ? How will the presence of a capacitor affect the magnetic ...
0
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1answer
25 views

Magnetic field of a solenoid vs magnetic circuit

The magnetic field in the middle of a solenoid is : $$B = \frac{\mu_0 N I}{L}$$ where L is the length of the solenoid The magnetic field in the air gap of a magnetic circuit with constant cross ...
-1
votes
0answers
21 views

Doubts wrt Electromotive force

The definition of emf states that when a cell is in open circuit , the potential difference between the terminals of the cell is called the emf. Now i dont understand that how can p.d. be taken into ...
0
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0answers
4 views

Working point of a transistor circuit [migrated]

I've stumbled upon this problem which involves a circuit with 2 transistors that are connected to each other. I'm trying to find a) the "working point" ($V_{ce}$, $V_{be}$, $I_c$, $I_b$) of each ...
4
votes
2answers
187 views

Will the two capacitors be charged in this circuit?

Is such a circuit possible to exist with the two capacitors charging? Because if we considered the outer loop using Kirchhoff's law we get: ℰ = q1/C1 + q2/C2 But since the two capacitors are ...
-1
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0answers
22 views

Two charged conducting spheres when placed in contact with each other [duplicate]

What happens when two charged conducting spheres of different radii are brought in contact with each other. How does it affect the charge distribution and field lines of spheres?
0
votes
1answer
30 views

Why is the electric field homogenous inside a circuit?

In a circuit between to poles of a battery, there is an electric field accelerating the charges in the wire towards lower potencial (but due to resistivity they only travel at drift velocity). Is ...
0
votes
1answer
18 views

How is a change in capacitance detected in a touch-screen?

So the screen has lines of conductors horizontally and vertically, seperated by a dielectric, and thus forming a grid of capacitators where the ones in one "row" are in parallell on the one side, and ...
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votes
2answers
63 views
1
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2answers
37 views

Steady state RLC circuit analysis

In an RLC series circuit let applied EMF be given $V=V_0\sin\omega t$, $$Z=Z_C+Z_R+Z_L=R+i\left(\frac{1}{\omega C}-\omega L\right)$$ $$|Z|=\sqrt{R^2+\left(\frac{1}{\omega C}-\omega L\right)^2}$$ Then ...
0
votes
1answer
28 views

Capacitor and inductive coil in AC circuit

Does increase in $L$ of inductive coil with variable no. of turns or $C$ of capacitor with changeable capacitance increase frequency of the circuit?
0
votes
1answer
42 views

Question for power and Ohm's law [closed]

I have two questions specifically. Can the usage of Ohm's law be utilized to predict current, voltage in circuits such as parallel, complex and series? How would I explain this? How does the power ...
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0answers
22 views

Power formulas? [duplicate]

Are different power formulas in circuits used for different reasons? For Example Power = V^2/R Power = I^2/R Power = VI