4
votes
2answers
150 views

Voltage drop due to a resistor

I'm afraid this question is going to sound rather dumb but here it is: Suppose I have a very simple circuit: one battery and one resistor. The sum of the voltages in this circuit has to equal zero. ...
0
votes
1answer
29 views

Potential Differences (Voltage) from Point Charges [closed]

Identical +1.8 micro Colomb charges are fixed to adjacent corners of a square. What charge (magnitude and algebraic sign) should be fixed to one of the empty corners, so that the total electric ...
0
votes
3answers
54 views

Transformers and DC voltage

Ok, if I have a transformer with 100 coils of the primary and 200 coils on the secondary and I connect a 9 volt battery to the primary, how many volts should I expect from the secondary coil? I know ...
0
votes
1answer
92 views

What's the relation between output voltage and time to boil water given the same kettle?

An electric kettle rated 220V, 2000W needed 10 minutes to boil water when it is half filled with water in Singapore where the output voltage is 220V. Estimate the amount of time needed to do the ...
1
vote
2answers
49 views

Finding the current in a parallel circuit [closed]

Two resistors are joined as shown. The top resistor receives a current of 3 A. What is the current in the other resistor? What is the current that enters at junction A? I'm confused on how the two ...
0
votes
3answers
62 views

How is voltage increased from a battery?

I have recently watched a video about a powerful Octa-copter that uses 30,000 Volt brushless motors to propell, the batteries however look quite small about a 19v laptop battery. How is the voltage ...
1
vote
3answers
70 views

How can there be a voltage when there is no current?

I'm told at school that the Electromotive Force (e.m.f) of a battery equals the potential difference between the terminals of the battery when there is no current. How is that possible? How can there ...
0
votes
3answers
64 views

What does raising voltage do?

If I raise the voltage of a wire from 0V to 1000V and then to 5000V, am I merely packing it with more and more electrons (with those electrons being trapped there until they find a path off the wire)? ...
1
vote
1answer
88 views

Formula for Electrical Arc Length

I was playing with some High-Voltage the other day, when a question popped into my head. Can you calculate length of an electrical arc? It probably would be proportional to :- 1. Voltage of the source ...
0
votes
1answer
59 views

Simple Parallel Electric Circuit [closed]

Ammeter (A1) and voltmeter (V) in series have parallel connection to another ammeter (A2). Currents in A1 and A2 are respectively 0.2 and 1.7 amp. Voltmeter's voltage is 6 volts. How should I find ...
2
votes
1answer
110 views

If I charge a battery using a much higher amperage, can it explode?

If I have a 12V 4Ah lead acid battery and use a battery charger that, let's say for example, can charge 10A, 50A, or 100A. If I theoretically turned it to 100A will the battery explode? I understand ...
0
votes
1answer
29 views

Form factor and average value [closed]

Why Our Electricity Flowing in the Sequence of 11kv,33,66,132kv,why not Flow in 10 kv,11,12,13,14 that Sequence.
3
votes
3answers
195 views

If the current is increased, is there more charge flowing or is it moving quicker?

Problem Current is the amount of charge that is flowing through a component per unit of time. For a given voltage, Ohm's law tells us that if we increase the resistance, then the current must ...
1
vote
1answer
43 views

What is the relationship between the verbal definition and the mathematical definition of some quantities?

I know this is probably an easy question, but it's been a while since I've studied physics and I've started reading some circuit analysis textbooks. I'm finding hard to understand the relationship ...
1
vote
1answer
286 views

The shape of the graph of the equation: $V= -r I + E$

I have recently collected data (for a school experiment) in order to measure the EMF and the internal resistance of a solar cell. The data complied with the equation: $V = -rI + E$, i.e. the voltage ...
0
votes
0answers
209 views

What would the graph between P (power) and i (current) look like if the graph between V (potential difference) and i is parabolic?

The answer is same... That us the graph between P and I will also be a parabola.... Similar to the graph between V and I. But how? Can anyone explain through mathematical approach ? I used ...
0
votes
1answer
86 views

Current vs Voltage Drive for Loudspeakers [closed]

Please see this article: here I don't know enough EMFT to comment on this but I am working on other tasks for a wireless speaker system prototype called "Busker's Friend". Completing my Schaum's ...
0
votes
2answers
99 views

Voltage Drop and Charge Flow

I am hoping someone can help me with understanding voltage drop and charge flow. Here is what I think I know. The voltage drop through a circuit must equal the voltage of the battery source, and ...
1
vote
3answers
60 views

Electric Power $P$

In my textbook there are 2 formulas for electric power: $$\begin{array}{cccr} P &=& E/t &\hspace{10pt} (1) \\ P &=& VI. &\hspace{10pt} (2) \end{array}$$ What is the ...
-1
votes
1answer
25 views

Computing power based on weighted averages [closed]

I'm struggling to understand the reason why I'm getting different results with two apparently similar ways to compute the power consumption (over multiple time intervals) of an electrical circuit. ...
-1
votes
1answer
119 views

Electric shock from a frayed wire

Let's say it's a laptop charger not connected to a laptop, and it is frayed near the tip. I am guessing about 20Volts runs through that area. Now if a person touches a bit of plastic below the frayed ...
2
votes
2answers
51 views

Electric motors and change in flux

"When a current passes through an electric motor, the magnetic force on the motor causes a torque on the loop of wire causing it to turn". However, when the loop rotates, there should also be a ...
2
votes
1answer
86 views

How dangerous is a parallel plate capacitor which is used in physics demo experiments?

How dangerous may it be when experimenting with a parallel plate capacitor typically used in physics demonstration experiments? Take for example this one (that's what I use): ...
0
votes
2answers
242 views

What actually happens at the microscopic level in a Zener diode in reverse bias?

A Zener diode is used as a voltage stabilizer. The graph of current vs voltage of Zener diode clearly shows that there is a constant voltage across Zener after the breakdown voltage as the current ...
1
vote
2answers
254 views

Physics of batteries (volts vs charge)

Car batteries are usually 12 V. What is the difference between buying a car battery and hooking up a bunch of cheap household batteries in series? Both would register at 12 V. I assume that cars need ...
0
votes
2answers
299 views

How do voltage and voltage drops over a circuit relate to work done?

I have a few remaining uncertainties when it comes to voltage. I numbered the paragraphs in my thought sequence for easier reference. In a series circuit, I know voltage is the electric potential, ...
1
vote
3answers
845 views

Questions about voltage

For some reason, I feel like the concept of voltage is escaping my grasp. I've done much research on these forums and through texts, and come across answers that seem quite well thought out, but still ...
0
votes
3answers
72 views

Capacitor related query

Why does a capacitor charge only upto the voltage of the source? I mean in an r.c. circuit if we have a resistor that is in series with the capacitor then because of the potential drop there will be ...
0
votes
0answers
44 views

Formation of magnetic field in an inductor

I can't really imagine the way the magnetic field would be created due to electron flow in an inductor. We say that in a straight current carrying conductor the magnetic field follows the thumb rule. ...
1
vote
3answers
114 views

Relation between voltage and current [duplicate]

What I know is that voltage is the electrical pressure which is required to drive the electrons in a circuit. According to that we have higher currents when there is a high voltage. Ohm's law confirms ...
0
votes
1answer
138 views

Voltage and current in parallel circuit

I am having a bit of a tough time understanding the following: ...
0
votes
1answer
272 views

Use kirchhoff's second law to deduce the resistance R of the resistor [closed]

Using what I learned so far, i constructed an equation like this: $$30V=(I_{1}\times 20\Omega)+10V+(0.2A\times 10\Omega)+(I _{3}\times 10\Omega)+(0.5A\times R)$$ Which is clearly not solvable on ...
0
votes
3answers
195 views

Current without voltage?

Suppose you have a 120 volt, 20 amp circuit which only has a light bulb connected. When measuring the voltage going to the light bulb my meter reads 120 volts. The basics taught me that a circuit is ...
0
votes
1answer
991 views

How to evaluate, how much current flows in the circuit?

Please take into advisement, that I'm quite a beginner in subjects of physics and especially about electricity. Lately I've decided, that I want to learn more on basics of electronics and I've started ...
2
votes
3answers
167 views

Why are high voltage lines “high voltage?”

If I have two spheres of the same size and one sphere has a small amount of charge compared to the other that has a lot more charge, then clearly the sphere with the larger charge has a larger voltage ...
1
vote
0answers
405 views

Finding potential difference (PD) between two points [closed]

How do I find the potential difference between two points in a circuit without using Kirchhoff laws?
-3
votes
1answer
232 views

Why is it written 'High voltage' in danger boards if current is the one which actually causes the shock?

After reading the answers given to this question I could understand that the amount of shock is dependent on the current and not majorly on the voltage even-though in some cases it depends. But, in ...
0
votes
5answers
8k views

Why does voltage remains same over Parallel Circuit

Why does voltage remains same over parallel circuit. If a resistor is connected in the circuit some of the charge should be transformed into heat and make a lack of charge after the resistor (in my ...
2
votes
1answer
94 views

Why isn't this working? [closed]

I just broke a 120mm computer fan in name of science and now I'm pissed; can anyone explain why this doesn't work? : The battery should create a potential difference across the motor, causing the ...
0
votes
3answers
219 views

Potentiometer voltage change

I'm trying to understand simple things about electricity reading allaboutcircuits.com web. This chapter includes image which´s principle I don't understand. Here it is: When supplying constant ...
0
votes
1answer
3k views

Why is Energy = Voltage x Charge, and how to prove that?

As you know the equation $\mathbf{E=V\times Q}$. Where: $\mathbf E$ is the energy measured in joules, $\mathbf V$ is potential difference (Voltage), $\mathbf Q$ is the charge. So my qustion is: ...
1
vote
1answer
321 views

Electric power for current density

The electric power produced by a current $I\in\mathbb{R}^+$ and a voltage $V\in\mathbb{R}^+$ is $$ P = IV. $$ Now the current is given as an (alternating) current density ...
0
votes
1answer
67 views

Would the empirical behavior of a simple circuit match my model of it?

I have a practical problem in E&M which has baffled me and and my electrician. The copper water pipes in my house are carrying a current of small potential (~1V) AC current. Here is my ...
0
votes
0answers
106 views

About electric current analogy

my teacher gave me this analogy to the electric current , the wire is like a pearl necklace where the pearls can move, the current or the movement of electrons is like putting your fingers between 2 ...
0
votes
2answers
5k views

What happens when non-equal voltages are put in parallel? [duplicate]

If two batteries, say 2 volts and 5 volts, are connected in parallel, are there any problems? The higher voltage will then want to flow out, but also towards the lower 2 volt battery end, right?
2
votes
1answer
97 views

Help Understanding Non-conservative Fields

While watching a video lecture, I became uncomfortable with the results, (around 35 mins). The professor draws an electric circuit with a 1V batter, and two resistors (1 and 9 ohms). He then ...
0
votes
1answer
3k views

Volts, Amps, and Practical Electrical Knowledge [duplicate]

I've heard people say that high amperage or high voltage is dangerous to humans-aren't they both? And what are the advantages to high amperage versus high voltage? And how do you generate one or the ...
0
votes
1answer
2k views

How electrons act under rotating magnetic field?

I study Power Engineering in University. Today I asked my lecturer to explain me exactly how atom's electrons act under spinning rotor's magnetic field, that generated dynamic electricity. But he even ...
0
votes
4answers
350 views

Why is there a potential difference?

The question then asks for the potential difference between $X$ and $Y$, which is claimed to be $3.6\text{ volts}%$. Why would there be a potential difference in this case? If I connect a lightbulb ...
2
votes
1answer
103 views

Which of these two methods is correct for calculating current?

I recently came across a question, for which I saw two possible methods of finding the solution. I was required to calculate the "current flowing" $I$ when given the voltage $V$, frequency $f$, total ...