0
votes
1answer
85 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 ...
0
votes
2answers
24 views

Question about indutive loads in power system [closed]

Our home appliances are mostly resistive loads and the bill we pay for consuming power is actually real power. If we use more inductive loads at our home, will it just cause problems in power factor ...
-1
votes
1answer
26 views

Is watt unit depended on turbine speed

I'm new to electronics. I have a doubt. That is... Is watt unit depended on speed of turbine ? In my mind When turbine rotates fast the power in increase. Is it right ? Please help me. Thanks for ...
0
votes
0answers
8 views

Transient Stress and Piezoelectric Generators

From what I can gather, the piezoelectric effect links mechanical stress to the potential difference across a material, with a two-way relationship between the two (motor or generator). I don't know ...
1
vote
1answer
46 views

Power delivered by a plug

Ok so i know that (in the UK) the voltage of a mains supply is 230v. But when we plug a item e.g. a tv in to it what determines how much power is drawn from this supply. I presume it is the current ...
2
votes
1answer
76 views

What exactly is three phase power? [closed]

What is three phase power? How does it differ from normal AC current?
0
votes
2answers
32 views

How is the wattage of electrical appliance specified?

What does it mean by a bulb is 60 Watt or 100 watt (I know it means it emits 60 or 100 Joules of energy per second, but at what conditions)? Which one glows brighter when connected in series?? What ...
0
votes
1answer
57 views

Calculating kWh from time series of kW

I have a time series of kW where each sample is measured at regular intervals (10 seconds). Could anyone explain to me how could I calculate the total power consumed (kWh) over an hour? Thanks
0
votes
2answers
130 views

How much electricity can be produced by my thermoelectric generator?

I am using a thermoelectric cooler from a pc's heatsink to produce electricity. Its size is 30mm by 30mm. I will cool it on one side at -10 degree Celsius and the other at 24 degree Celsius. Can ...
0
votes
1answer
69 views

Which thermoelectric effect is better?

I am doing an experiment which requires the thermoelectric effect. I know about the Seebeck and the Peltier effects. Well, from what I have found till now on these topics is that they both can produce ...
0
votes
0answers
187 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
3answers
151 views

Different formulas for calculating power [duplicate]

$P=IV$, $P=I^2R$, $P=\frac{V^2}{R}$, what are the distinctions between these equations? How do you know which equation to use when?
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. ...
4
votes
4answers
262 views

Is a billion volt electrical transmission line possible?

Because $$ P_{\,\displaystyle\rm loss}=\frac{P^2R}{V^2} $$ in an electrical line where $R$ is the total resistance Why not use a $1$ billion volt line instead of a $800\,\rm kv$ line? Is there a ...
0
votes
2answers
79 views

How does one estimate the electrical power of a power plant?

I have two related questions that I would like help on: When a power plant creates power like the Hoover Dam, it can provide 2.07 GW of electrical power. My question is what does this mean? I assume ...
0
votes
1answer
341 views

Power loss and Joule's law of heating

I really can't understand the power loss law. If we have a wire carrying a $15\:\mathrm{V}$ and $1\:\mathrm{ A}$ going into an inverter, giving $150\:\mathrm{V}$ and $0.1\:\mathrm{A}$, if we want to ...
0
votes
2answers
67 views

Calculating the power of a lightbulb [closed]

How do I calculate the power of a lightbulb? I have values but I don't know the equation to use.
-4
votes
2answers
359 views

Basic Physics Question [closed]

I'm having a difficult time answering this question. I think I'm just converting the units wrong somewhere: You're the CEO of a courier company, and you decide to select an electric car for your ...
0
votes
2answers
115 views

In which direction should flow of electric current be taken while solving problems?

Consider a simple circuit with a battery of $\theta\ \text V$s, and two resistors of $R_1 \ \Omega$s and $R_2\ \Omega$s connected in series. Let us assume that $R_1$ is connected nearer to the ...
-1
votes
1answer
126 views

There is no electricity at home,I need to light a 15W CFL Bulb.Can I Do it with the help of a hamster? [closed]

We know that i)avg speed of A Hamster is 30km/hr. ii)Avg mass of hamster is 1.5 kg. From the above info: Kinetic energy=1/2 X mass X velocity^2 So, K.E=1/2 x 1.5 x 30 x 30 ...
1
vote
1answer
312 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
2answers
1k views

Light bulbs, Wattage meaning? [closed]

Light bulbs, Wattage meaning? Two incandescent bulbs (120 V, 25 Watt) and (120 V, 500 Watt) connected to the same batteries. Which one shines brighter? And why?
3
votes
2answers
1k views

Is it possible to get energy from electrical wire using induction?

Pardon me if this is a stupid question but my physics courses are from a long long time ago and I was a teenager back then. ;) Electricity in a wire generates electromagnetism, right? Would it be ...
0
votes
2answers
8k views

Confusion about P=VI and V=IR

If we look at $P=VI$, we see that if the current doubles then the potential difference is halved but this doesn't seem to make sense according to $V=IR$. If we look at that equation, since the ...
1
vote
3answers
5k views

Average power dissipated by a resistor on AC current

So let's say we have an AC current of 120 V at 60 Hz. Then i's waveform would be $$f(t) = 120 \sqrt{2} \cos(2 \pi 60 t)$$ Or rather the amplitude times $\sqrt{2}$ times $\cos(2 \pi ...
2
votes
2answers
200 views

Can wireless power transfer harm organic life by anyway?

Now, humanity can beam 50-60 watts power through 10 centimeter-thick concrete block. Can such wireless power transfer harm us by anyways?
0
votes
1answer
122 views

Do you think it’s possible to make a power plant of the described kind?

We are working on a science project and try to engineer a power plant of a new kind. It is called Air HES (air hydroelectric station). The idea is described on our website. Do you think it is ...
1
vote
3answers
5k views

Two 60W-lightbulbs are connected on 220 V AC-voltage - how much electric power is spent by each lightbulb? [closed]

Two 60W-lightbulbs are connected on 220 V AC-voltage - how much electric power is spent by each lightbulb? There are two scenarios: In one, these two lighbulbs are connected serially, and in the ...
1
vote
2answers
423 views

Calculate power $P=V \times I$

I have an adapter which mentions like this... Input: 100-240V~1.8A 50-60hZ So how much power does it really consume? I just knew ...
1
vote
5answers
352 views

How do electrical devices suck electricity?

If the electric potential is 220V and some device needs 1500watts then how does it suck exactly that amount of electrical energy from outlet?
0
votes
3answers
881 views

How can AC source with different voltage provide same power

As some of us maybe aware, USA mains connection is 110 V while those in Asian countries are 220 V. How is it still possible for the Adapter to provide the necessary power to the device, say a laptop, ...
2
votes
5answers
22k views

Charging 12V 150Ah battery

I want to charge a 12V battery of 150Ah with a solar panel. The solar panel specs is 12V, 25 Watt. Can anyone please provide me how to calculate that how much time it will take to charge the battery? ...
2
votes
2answers
1k views

Total power consumption of electric device

For some electric devices, like a fan or air conditioner, I read about their power consumption in watts on their specification guide. Does it tell about the power at normal or full speed? or Does the ...
1
vote
2answers
2k views

How do I calculate the power consumed by a lightbulb?

I'm studying a lightbulb and its variable resistance, given by the expression: $R(T) = Ro[1 + α(T-T_0)]$, where $R_0$ is the resistance of the lamp at $T_0$. In this case, $R$ is not given by Ohm's ...
1
vote
2answers
387 views

Why doesn't a phone charge faster, rather than slower when it is in use

In Physics class, we were building parallel circuits, and as more lights were attached in parallel, they got brighter (as more power was being provided to the lights, and the resistance decreases). ...
9
votes
3answers
5k views

Why do power lines sag when they are heated up?

I was reading some information about the 2003 power blackout in the Northeastern US. Beginning early in the afternoon of August 14, 2003 big transmission lines began to fail in First Energy's ...
2
votes
4answers
1k views

Do Alkaline batteries, $\mathrm{NiMH}$, rechargeable alkaline, Lithium $\mathrm{AA}$, all have similar MAX POWER?

So in physics, one smart teacher told me, $$ V = IR $$ or $$ I = \frac{V}{R} $$ but it is not always true, because $P = VI$ and each power supplying device (such as battery) has a "maximum power" it ...