Resistance Definition and 1000 Threads

Suppose that there is a positively charged particle and a negatively charged particle in free space. The electric field of the positive charge causes a difference in potential between the position of the negatively charged particle and the positively charged particle. This, causes the negatively...

Hello. The measurement of electrical resistance as a function of the superconductor's temperature yields fundamental insights into its properties. The Critical Temperature, Critical Current Density, and the Critical Magnetic Field, can all be obtained through variations of a basic experiment. I...

Homework Statement In the interval between the freezing point (ice point) of water and 700.0deg-C, a platinum resistance thermometer is to be used for interpolating temperatures from 0 °C to the melting point of zinc, 692.666 K. The temperature, in Celcius or Centigrade, is given by a formula...

I wanted to do a science experiment and it is very important that i learn the electrical resistance of carbon dioxide. From what i would guess, this may be wrong, but carbon dioxide and the atmosphere on Earth probably have a similar electric resistance due to the fact carbon dioxide already...

1. The problem Given a circuit with a 30V source and five resistors. The circuit can be drawn as two boxes. Resistor 1 (R1 = 300ohm) is in series with the source. R2 (300ohm) in the middle of the two boxes, and the remaining resistors (550 ohm) in series at the other side of the box. The...

Homework Statement The two voltmeters have very large resistance, the 3 ampere meter have resistance of ##0.5\Omega## each one. ##V_1## show twice as much voltage as ##V_2##, ##A_1## shows ##0.4A## and ##A_2=A_3=0A## a. Find ##R_2## b. Find the internal resistance of the battery Homework...

I'm a games programmer working on a (simple, so far) physics engine for a driving game. Right now I'm interested in acceleration, and in particular trying to estimate the forces that go into it. I've got basic data for a bunch of cars (0-60 time, 0-100 time, top speed, mass) and a brute-force...

From my understanding, transformers allow electricity to travel long distances with minimal energy loss because they initially use a step-up transformer which reduces the current (which reduces the heat loss and hence energy loss). However, I do not understand how a step-up transformer manages...

Homework Statement What is the Total resistance in Question 38. Homework EquationsThe Attempt at a Solution I tried drawing the circuit again splitting up the series and parallel but i got the wrong answer. The answer is 92. Like i know that the 60 is parallen to 15 and the 15 is parallel to...

Homework Statement Problem in photo... Homework Equations Don't know... Cause velocity ( m/s) isn't acceleration and therefore you can't find Fnet... So I don't know The Attempt at a Solution Does it have anything to do with finding Fn than multiplying that?

Hello, A diode is represented by an EMF equal to the electric field in depletion zone plus a resistance. This resistance is obtained from the I/U characteristic of a diode. My question is, this resistance is due to what? The resistivity of P and N junctions or because in forward bias case...

Can someone explain three wire and four wire RTD circuits in terms of how the lead resistances affect the voltage output ##V_o = \frac{R_3 V_s}{R_2 + R_3} - \frac{R_4 V_s}{R_1 + R_4}## Also, in the case of a three wire, what is the purpose of Lead C?

Homework Statement How to calculate the value of total resistance RT in the shown circuit? Homework EquationsThe Attempt at a Solution I used Kirchhoff` first law: i1+i2=I where i1, i2 and I are the current passing through R1, R2 and the total current in the circuit, respectively. similarly...

Homework Statement In the fig all resistors have resistance R. If pd of V is applied across AB. 1)What is the outcome of joining C and D 2)Whats is the pd across CO 3)what is the resistance across A and B 4)What is the resistance across AO Homework Equations V=IR 1/∑R=1/R1 +1/R2 The Attempt...

Homework Statement In the Circuit(pic attached) the following resistor combination is found. All the resistrs in the figure has resistance R ohms. What is the total resistance across AB? Homework Equations V=IR 3. The attempt at a Solution between point A and B there is only one resistor so i...

Homework Statement What is the effective resistance of this circuit? Homework Equations The answer given is 3A. so it means the total effective resistance is 4 ohm. But my answer is 4.4 ohm The Attempt at a Solution My attempt: 1/(1/6 + 1/4)+2 = 4.4 ohm

Homework Statement A ball is thrown vertically upward with an initial speed of v0. It experiences a force of air resistance. The positive direction for all vector quantities is upward. Does the magnitude of the acceleration of the ball increase, decrease, or remain the same as the ball moves...

Hi! I can't find the method of the solution to this question, it was an exercise on an exam.. There are two grounding electrodes buried in the ground. We make three measurments. First, we measure the first electrode's grounding resistance, which is: 6 ohms. Then, the second's: 7 ohms. Then the...

I want to understand what happens to the energy inputted into a simple machine if there is no resistance or load. For example, let's say you have a U-shaped tube of water with greater surface area on the left side. If a piston applies pressure to the left side and there is no piston on the right...

Hello, I am trying to find the magnitude of the resistance force of an object moving down a slope. The question I was given says: A skateboarder heads down a gentle slope (Θ=5°) at a constant speed of 5m/s. Calculate the magnitude of the resistance force. Using the equation mgSinΘ - ma = R, (g...

imgur: http://i.imgur.com/9VILpYL.jpg Now, I can easily solve this by applying the formula P_R = \frac{(\Delta V_R)^2}{R} and get all the correct answers. However, the answers feel strange to me intuitively. In the formula above, lowering the resistance increases the power that is dissipated...

I'm not sure if I'm supposed to post this here, if I'm not, I'm sorry. That being said, what kinds of rubber can be heated up to 30 degrees c without degradation but can be melted. I would like to sandwich a heating filament between two sheets of rubber and seal them together with heat.

Homework Statement Assume the electric potential is zero at the negative terminal of the battery. Calculate: a). the equivalent resistance of the circuit b). the electric potential at position a c). the magnitude and direction of the current through each resistor Homework EquationsThe...

Homework Statement Homework Equations F=ma The Attempt at a Solution As the diver's velocity increases, then force F due to air resistance would increase, so D is out. And C is out too, as air resistance would be equal to its weight at terminal velocity. The answer is B, but how do we know...

I am currently learning about Thevenin equivalent circuits and was posed with the question attached to this post. I was wondering why I3 is equivalent to the current formed by a short circuit between nodes a and b. Shouldn't the current between a and b be I1 + I2 + I3 since in a short circuit...

Homework Statement I collected data for an experiment involving air resistance. We made paper disks and timed how long they took to fall over a fixed distance. We changed the radius of the disk. We found that as you increase the radius they take longer to fall. I am trying to explain my results...

In charge density wave systems in paper http://journals.aps.org/prb/abstract/10.1103/PhysRevB.37.10055 subharmonic steps are detected in experiments from the differential resistance ##\frac{dV}{dI}##, instead of from ##I-V## characteristic. Since the charge density wave resistance is shunted by...

Homework Statement My task is to plan and carry out experiments which show that the resistance of a conductor is proportional to the conductor's length. I have access to the following equipment: http://imgur.com/a/GuqUX Amperemeter, voltmeter, electricity, ruler som other werid things and...

Homework Statement Homework EquationsThe Attempt at a Solution This is how I drew it (in pencil) , but there should be a rheostat connected in series with the power supply, why?i can already calculate the resistance straight away by V/I

1. Homework Statement Homework Equations P=IV, =I2R =V2/R The Attempt at a Solution For zero resistance, I used P=V2/R formula, and sub. R=0 , power would be infinite. But if I sub. Into P=I2R, power will be zero. The correct answer should be zero. But why do we need to use the second...

What will be the color code of a zero Ohm resistance?

Homework Statement Suppose you drop a feather and a steel ball of equal masses (0.014 kg) at the same time from a height of 2.2 m and you are told that the feather hits the floor 3.5 s after the steel ball. Estimate the value of the terminal velocity of the feather in air. Then, estimate the...

Homework Statement If we neglect air resistance, then the range of a ball (or any projectile) shot at an angle θ with respect to the x-axis and with an initial velocity v0, is given by R(θ)=v_0^2/g sin(2θ) for 0 ≤ θ ≤ π/2 where g is the acceleration due to gravity (9.8 meters per second per...

In short circuit it is said that there is no resistance. So the current produce heat and wire is burnt. But as the rise in temperature increase the resistance then in short circuit heat must rise the resistance. How can we say there is no resistance in short circuit?

Hey everyone, I had a few questions about resistance of wires and heating. I'm a materials engineer looking to replace traditional copper with something more lightweight, however, the alternatives have high resistance. For comparison say copper wire has .01 ohm/ft the other material could be 1...

Homework Statement After performing a lab experiment to determine the conductivity if Pasco conductivity paper, I found the conductivity to be 0.195 Ωm. We found conductivity by graphing measured values of voltage (y axis) and the length (x axis) between the probes of a voltmeter that are...

Homework Statement Consider the voltage divider circuit below. The output voltage is with V0 =20v with RL removed ( RL= ∞Ω) from the circuit. With RL in the circuit and RL=380Ω , the output voltage is V 0=19.192 v . Determine values for R1 and R2. I attached a picture of the circuit...

Hello Forum, Electric current usually goes down the path of least resistance if it can. However, there are situations in which it prefers to go through a path of more resistance if the path of least resistance has no potential difference across. Are my statements correct? For example, see the...

In https://in.answers.yahoo.com/question/index?qid=20120918081153AARHhnA, It says that "1.When the length of the wire is doubled,its volume remains constant, " How come ? Volume is Area times the length.. How come it remains constant if the length of wire is doubled ??

Hi all, I've been a long time reader of this forum but haven't signed up for whatever reason. So thanks for the wealth of information and solutions to my headaches. I'm trying to figure out a coefficient of temperature equation and I'm having a hard time with the manipulation for some reason...

I've read all the posts about this, but I still can't get this one thing: Why does current decrease if a resistor is put into the circuit? 1) there's a circuit without an 'official' resistor, only a wire that has small resistance. 2) there's a circuit with an 'official' resistor, and a wire...

Hi guys, new here. Thank you for reading my post. I'm posting today because although I'm an engineer, I have some brain tumors that have impeded my ability to process most math above basic algebra (despite the fact that prior I'd gone all the way through stats in college). It didn't really start...

Homework Statement Here is the homework problem I was given: The Attempt at a Solution Above is the work that I began, however, I have an overwhelming feeling that I am incorrect and also I don't know how to continue to the next part/parts. Would someone please help me? Thank you H

Question: Problem 1 of the attachment. https://drive.google.com/file/d/0B72RSYQDrg1vcm84SmxFcjhyOFk/view?usp=docslist_api Homework Equations For parallel resistors: 1/R=1/R1 +1/R2 The Attempt at a Solution I am sure the resistors are not in series but they also don't look convincing enough to...

Homework Statement Homework EquationsThe Attempt at a Solution (a)I think there are two pairs of resistances are in parallel,one pair is the 40ohm and 50ohm resistances,and the other pair is the 30ohm and 60ohm resistances.But I'm not to sure:oldfrown: So the Req I've calculate is 152.2ohm...

Homework Statement IMPORTANT:There is an error in the statement.α and β are in C not K 2. Homework Equations R=Ro(1 +αt+βt2) The Attempt at a Solution I really don't know what to do because if I isolate t in the equation it will give me the temperature on the ideal gas scale whereas the...

I'm confused about the resistances of common electrical appliances. v=ir So I was reading something about how fast iphones charge with different chargers and it got me thinking about the resistance of things like phone batteries. So it said that it could charge at 5V and 2 amps, but also at 5V...

Homework Statement 1) A typical wall construction for a single-family residence might consist of 0.375 inches of outer sheathing (insulating board, hardwood siding, etc.), 3.5 inches of mineral fiber insulation and then a 0.375 inches inner surface (gypsum, etc.). Typical thermal...

Hi What would be the mathematical approach for calculating the resistance between two close points on an infinite plane of resistive material? And if the plane was circular/square/rectangular with the two points at the cente?

I am having a difficult time solving the question in Step 2 of the attachment. The question is "Use the equivalent-circuit model of the uA 741 to find: The voltage gain Av=vo/v1, the input resistance R1, and the output resistance Ro of the amplifier circuit. Attempt at solution: I used the...