What is Electric current: Definition and 172 Discussions
An electric current is a stream of charged particles, such as electrons or ions, moving through an electrical conductor or space. It is measured as the net rate of flow of electric charge through a surface or into a control volume. The moving particles are called charge carriers, which may be one of several types of particles, depending on the conductor. In electric circuits the charge carriers are often electrons moving through a wire. In semiconductors they can be electrons or holes. In a electrolyte the charge carriers are ions, while in plasma, an ionized gas, they are ions and electrons.The SI unit of electric current is the ampere, or amp, which is the flow of electric charge across a surface at the rate of one coulomb per second. The ampere (symbol: A) is an SI base unit Electric current is measured using a device called an ammeter.Electric currents create magnetic fields, which are used in motors, generators, inductors, and transformers. In ordinary conductors, they cause Joule heating, which creates light in incandescent light bulbs. Time-varying currents emit electromagnetic waves, which are used in telecommunications to broadcast information.
Consider an electric circuit at rest in the lab inertial reference frame. The circuit carries a steady electric current I. What is the current in the circuit as observed from a different inertial reference frame with a velocity of v relative to the lab frame?
Thanks in advance for your answers
Hi,im trying to work out this problem but i am slightly confused by the way in which it is phrased.It states:
Three parallel wires,arranged in the form of an equilateral triangle, of side length 10cm,each carry a current of 50A in the same direction.Calculate the force on anyone wire due to...
Hi
Does there exist a material whose state it is possible to change from a solid to liquid by application of electric current? Obviously a large enough current will melt anything, but what I mean is is there some other mechanism, other than brute force heating that can cause a solid to...
I have just done an experiment of magnetic fields around electric current in straight wire by using the seach coil.
I have 2 questions about this...
(1)why is this necessary to ensure the search coil is at the same level as the wire?
My anwser:If the seach coil is not at the same level as...
I seem to be having a problem getting this. I can get the first question, it is .65 A. But I can't seem to figure out the potential at point B. I used Vab = I2 * I1 but it still doesn't work.
In which of the following situations is an electric current not produced?
a. a loop of wire rotates in a steady magnetic field
b. a loop of wire is stationary in a steady magnetic field
c. the magnetic field through the loop is increasing
d. the magnetic field through the loop is decreasing...
Can anyone explain the concept of effective resistance between two points in a circuit. There are , on an average 6-7 resistors connected in every possible way in between the 2 points
for exampe refer to H C Verma questions
same for potential difference
How does a magnetic field generate an electric current?
Can someone explain this to me in simple terms? Or is there a website that might help me understand this?
Thanks
A 111 V electric iron draws 8.9 A of current. How much heat is developed per hour? Answer in units of J.
P = IV
P = U/t
U = IVt
U = 8.9(111)(60) = 59274 J
Apparently I'm wrong and I don't know why.
I'm currently stuck on this question on the image attachment. Any help would be definitely ppreciated.
Ok, so from what I understand, it asks what is the current that passes through the fixed line.
For part (a), I see that the current is 'discontinuous', and I'm not enitrely sure how to solve...
I did all the word but my answers are not matching my books?
1) Can a 2.5 mm-diameter copper wire have the same resistence as a tungsten wire of the same length? Give numerical detials. Answer, yes, 4.6 mm
Here is what I did:
( p = resistivity )
R = p(L/A) so I set R(Cu) = R(tug) and...
Can anyone help me with this question? Thank-you
A net charge of 51 mC passes through the cross-sectional area of a wire in 10.0 s. What is the current in the wire? How many electrons pass the cross-sectional area in 1.0 min?
I know that the current is .0051, but I'm having trouble finding...
What is electric current?
Let me explain my idea of it with an example of a long wire connected to the two terminals of a battery. The battery applies an electric field to the surrounding, causing a shift in the position of the electrons of the wire, especially the ones nearby. The speed and...
hey guys, here's my problem...
coil connected to a 240 V (rms) ac line has a resistance of 34 ohms. what is the average power used
(.5)V^2 /R so Pav = 847 W
then it asks what are the min and max values of the instanteous power...
This selection comes from the Serway . Beichner, Physics for Scientists and Engineers text that many undergrads are (I'm sure) familiar with!
I've looked at this problem on 3 different casual occasions and on one test and still have yet to arrange the concept in my mind...
"In the Bohr...
A power station delivers 620kW of power at 12,000 V to a factory through wires with total resistance 3.0 ohms. How much less power is wasted if the electricity is delivered at 50,000V rather than 12,000V?
I cannot quite picture what is going on in this problem. Is this a series circuit...
The equation for resisitivity is R=rho*(L/A), and the equation for current is I=V/R. So for the R equation I plugged in the numbers, changing cm to .1 m, and got 30 ohms. I then divided 110 volts by 30 and got 3.7 (rounded to two sig figs), and my answer is not being taken as correct. The...
I would like to understand this problem a bit better...
A small city requires 10 MW of power. Suppose that instead of using high voltage lines to supply the power... the power is delivered at 120 V. Assuming a two wire line of 0.50 cm diameter copper wire, estimate the cost of the energy lost...
Hiya!
I have a problem that's got me confused to solve. I want to use ohms law but not right. Here is the problem.
A nichrome wire has a radius 0f .5 mm and resistivity of 100 x 10^-8 ohm.m. If the wire carries a current of .5 A what is the voltage across the wire? The length of the wire is...