# What is Circular loop: Definition and 64 Discussions

A circular economy (also referred to as "circularity") is an economic system aimed at eliminating waste and the continual use of resources. Circular systems employ reuse, sharing, repair, refurbishment, remanufacturing and recycling to create a closed-loop system, minimising the use of resource inputs and the creation of waste, pollution and carbon emissions. The circular economy aims to keep products, equipment and infrastructure in use for longer, thus improving the productivity of these resources. Waste materials and energy should become input for other processes through waste valorization: either as a component or recovered resource for another industrial process or as regenerative resources for nature (e.g., compost). This regenerative approach is in contrast to the traditional linear economy, which has a "take, make, dispose" model of production.In recent years, concepts based on (re-)cycling resources are increasingly gaining importance. The most prominent among these concepts might be the circular economy, with its comprehensive support by China and the European Union. There is also a broad range of similar concepts or schools of thought, including cradle-to-cradle laws of ecology, looped and performance economy, regenerative design, industrial ecology, biomimicry, and the blue economy. These concepts seem intuitively to be more sustainable than the current linear economic system. The reduction of resource inputs into and waste and emission leakage out of the system reduces resource depletion and environmental pollution. However, these simple assumptions are not sufficient to deal with the involved systemic complexity and disregards potential trade-offs. For example, the social dimension of sustainability seems to be only marginally addressed in many publications on the Circular Economy, and some cases require different or additional strategies, such as purchasing new, more energy-efficient equipment.

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1. ### Bead sliding on a Vertical Circular Loop versus in Free Fall

I can evaluate the first beads motion easily A to B is -2Rj considering the point B as y=0 the motion of the bead will be -gt^2/2+2R=0 which implies t=2√(R/G) , this is ok but what I am struggling with is A to C I can see that the angle between the beads weight and it's negative normal force...
2. ### Magnetic field affecting a circular loop

If the magnetic field is constant then no change in flux will bring no induced emf nor any induced current. With the loop is in rest position the external magnetic field will exert a force but to calculate that force with the help of magnetic field isn't obvious. If this were a charged loop, the...
3. A

### Small bead - Circular loop Problem

Homework Statement: A small bead is fixed on a circular loop of radius R as shown in the figure below. The loop is rotating about YY axis with constant angular acceleration ‘α’. The loop starts from rest, then, the bead is in circular motion, then acceleration of the bead at instant ‘t’...
4. ### Circular loop of wire is concentric with a solenoid

Question: In Figure (a), a circular loop of wire is concentric with a solenoid and lies in a plane perpendicular to the solenoid's central axis.The loop has radius 6.13 cm. The solenoid has radius 2.07 cm, consists of 8230 turns/m, and has a current i_sol varying with time t as given in Figure...
5. ### Calculate Induced EMF in Circular Loop: Cylindrical Coordinates

In order to calculate for the curl of the induced electric field for a loop moving in a uniform magnetic field, and using the cylindrical coordinate system for a curl, it's my understanding that since the B field is in the 𝑧̂ direction, then so is the partial time derivative of B, and therefore...
6. ### Calculating Centripetal Acceleration in a Vertical Loop

$$mg(0.45) = mg(R + R \cdot cos(\frac{π}{3})) + \frac{1}{2}mv^2$$ $$v^2 = g(0.9 - 3R)$$ The centripetal acceleration during the "flying through air" will be given by gravity $$mg \cdot cos(\frac{\pi}{3}) = \frac{mv^2}{r}$$ $$R = \frac{1.8}{5}$$ But my book says $$R = \frac{1}{5}$$
7. ### E-field generated by constant current in a circular loop

Homework Statement Discussions of the possibility of a tangential E-field external to a current-carrying conductor must include a voltage source and a return path. Here the problem is reduced to (we believe) the simplest possible geometry. Assume that a circular conducting loop has constant...
8. ### Radiation field of charge moving in a circular loop

Homework Statement [/B] I need to calculate de radiation field produced by a charge moving in a circular loop of radius a, considering the motion is not relativistic and zone of radiation (far field) .Homework Equations The scalar potential is: $$V=\int \dfrac{\rho(x')}{|x-x'|}d^3x'$$ The...
9. ### Field of a circular loop around its axis issue

Good , i want to derive the formula for field of a circular loop around its axis but i was stucked with the following point: they consider dl perpendicular to r ! why is that?? many thanks in advance!
10. ### Flux induced in a circular loop

Homework Statement I have a circular loop with a radius of 1 m. The center of the loop is located 2 m away from a infinitely long current carrying wire, with ac current I. Find the flux in the circular loop Homework Equations Φ = ∫ B ds The Attempt at a Solution I've found a lot of examples...
11. ### Faraday's law -- circular loop with a triangle

Homework Statement A circular coil with radius a is connected with an equilateral triangle on the inside as shown in the figure below. The resistance for each section of the wire is labeled. A uniform magnetic field B(t) is pointing into the paper, perpendicular to the plane of the coil. B(t)...
12. ### Induced Voltage of Rotating Circular Loop

HI! I'm a student, this question appeared in one of the old tests. I though I had it solved but apparently I must have missed somewhere. Could someone please at least hint me where I went wrong? Homework Statement Thin wire is wound into circular frame with radius ## r = 0.05m ## which...
13. ### Displacement Function of an Idealized Circular Loop Coaster

Homework Statement Suppose we have a roller coaster cart of mass m, which may be approximated as a point mass for our purposes. Ignoring friction and air-drag, what is the displacement of the cart as a function of time? It enters the loop with an initial velocity $$v_0 \hat i$$ and the radius...
14. ### Tension in a flexible circular loop

Homework Statement A small circular flexible loop of wire of radius R carries a current I. It is placed in a uniform magnetic field B. The tension in the loop will be double if A) I is doubled B) B is halved C) r is doubled D) both B and I are doubled. Homework Equations The Attempt at a...
15. ### Question about Magnetic induction of circular loop

Homework Statement Homework EquationsThe Attempt at a Solution This is what i did about (a) but i don't know how to approach (b), it doesn't have x,y components, only Bz component.
16. ### Magnetic field in a circular loop

Homework Statement A conductor consists of a circular loop of radius R and two long, straight sections as shown in the figure. The wire lies in the plane of the page and carries a current I. (a) What is the direction of the magnetic field at the center of the loop? (b) Find an expression for...
17. ### Physics Magnetism - Wire Carrying Current in a Loop

Homework Statement This is a theoretical question, one I'm not sure about. It just randomly popped into my head. Say there is a jumbled wire, one in a glob shape but not overlapping. (Like a deformed circle, or maybe just a rectangle). Assuming we are in a place called "physics utopia" where...
18. ### Height in conservation of energy problem

Homework Statement A very Slippery ice cube slides in a vertical plane around the inside of a smooth, 20 cm diameter horizontal pipe. The ice cube's speed at the bottom of the circle is 3.0 m/s Vi = 3.0 m/s Height at top= 2(.20) = .40 Vf = ? Homework Equations KE(initial) + PE(initial) =...
19. ### Circular loop in magnetic field

Homework Statement A circular single loop of wire with a diameter of 20.0 cm lies in the plane of the paper in a region of space that contains a 1.75 T magnetic field pointing out of the paper. a) Determine the magnetic flux through this loop. b) If the diameter of the loop changes from 20.0...
20. ### Magnetic fields in circular loop

If I have a some a wire and I took part of it and created a circle. If I want to calculate the strength of the magnetic field at the center of it. I should just use the magnetic field equation for the circular loop, shouldn't I? ## B = \frac{U_o N I}{2R} ## and I shouldn't care about the...
21. ### Magnetic field strength for circular loop

When deriving the magnetic field strength due to a circular loop at some distance away from it's center (using Biot-Savart's law), why is the angle between ds and r 90 degrees? This is a youtube video with the derivation, see 5:55
22. ### Electromotive force (EMF) of a circular loop wire

Hi, so, I got help from this homework problem by posting it on chegg, but I want clarification. A circular loop of wire of radius 12.0 cm is placed in a magnetic field directed perpendicular to the plane of the loop and into the page. The field is decreasing at a constant rate of 0.050 T per...
23. ### What is the self inductance of a circular loop of wire?

If current I passes through a circular loop of radius R,then what will be the self inductance of that loop? (calculating flux through the loop leads to calculating magnetic field at every point inside the loop which is an elliptic integral.)
24. ### Magnetic field of a circular loop

Homework Statement A circular loop of radius R is on the xy plane and the center is at the origin, the current is flowing in a counter-clockwise manner. a) Let Q=(a,0,a) be a point such that a>>R. Find Br and Bθ at Q. b) Let Q=(ha,0,0) be a point on the x-axis such that h<1. Find the vector...
25. ### Force on a Circular Loop Due to an Infinite Wire

Homework Statement A long straight wire carrying a constant current I1 and a circular wire loop carrying a constant current I2 lie in a plane. The radius of the loop is R, and its center is located at distance D from the straight wire. What is the magnetic force exerted on the loop by the...
26. ### Outside the origin circular loop current density

Hi, I'm trying to write the current density for such circular loop in spherical coordinates. For a circular loop of radius a that lies in the XY plane at the origin, the current density it's simply: \mathbf{J}= \frac{I}{2\pi\sin\theta}\delta(\theta-\frac{\pi}{2})\frac{\delta(r-a)}{a}\hat{\phi}...
27. ### A circular loop over a magnetic field directed outwards

Homework Statement There is a counterclockwise current I in a circular loop of wire situated in an external magnetic field directed out of the page as shown. The effect of the forces that act on this current is to make the loop Select one: a. expand in size X b. contract in size c...
28. ### Induced current in a circular loop

Hi friends..I'm struggling with an interesting puzzle...Suppose there is a circular conducting loop of radius 1/π cm, one half of which is made of a material with resistance 1Ω and the other half from a material with resistance 5Ω. If somehow, one managed to set up a changing magnetic field...
29. ### Using ampere's law for a circular loop

Homework Statement Sorry to bother you guys, I've heard that Ampere's Law is either ineffective for calculating the B field due to a circular loop or needs some modification (I wasn't sure which). I'm trying to figure out why this doesn't work so I can get a better understanding of Ampere's...
30. ### Circular loop with uniform magnetic field

Homework Statement A current carrying wire is bent into a circular loop with radius R and lies in the XY plane. A uniform magnetic field in the +z direction exists through out the plane of the loop. What is the magnetic force exerted on the loop? Homework Equations Fb = I lb sin (theta) The...
31. ### Force on a shrinking circular loop in a constant B field

1. A conducting loop is shrinking in a constant ##\vec{B}##-field that is perpendicular to the loop-axis. The radius of the loop is given by ##r(t)=r_{0}e^{-at}##. The resistance in the loop is ##R(t)=2 \pi \rho r(t)##. What force is needed to keep the loop shrinking like this?2. Faraday's law...
32. ### Force on a circular loop due to hypothetical magnetic field.

Homework Statement A hypothetical magnetic field existing in a region is given by ##\vec{B}=B_o\vec{e}_r##, where ##\vec{e}_r## denotes the unit vector along the radial direction. A circular loop of radius a, carrying a current ##i##, is placed with its plane parallel to the X-Y plane and the...
33. ### Vector potential of a current carrying circular loop

Consider a circular loop of radius R that carrys a uniform current I. We know(by Biot-Savart law) that the magnetic field it produces on its axis is given by \vec{B}=\frac{\mu_0 I R^2 \hat z }{2(z^2+R^2)^\frac 3 2} . But let's calculate its vector potential: \vec{A}=\frac{\mu_0}{4\pi} \int...
34. ### Electric field above a circular loop

Homework Statement Find the electric field a distance z above the center of a circular loop of radius r that carries a uniform line charge λ. Homework Equations $$E=E_r\hat{r}+E_z\hat{z}$$ $$E_r=\frac{\lambda}{4\pi\epsilon_0}\int_0^r\frac{1}{\mathcal{R}^2}\sin{\theta}\,dr$$...
35. ### EM , magnetic field at centre of a carrying circular loop

The question is to find the magnetic field at the centre of a current carrying circular loop of radius R, where the current = I Okay so I'm trying to do this by both Amp's Law and Biot Savarts Law, and I can't get my answers to agree. First method - Biot Savarts Law...
36. ### Direction of force on circular loop.

Homework Statement Find direction of force on circular loop http://pokit.org/get/img/b886e52efb703d47d09fa6e781c74461.jpg What would hapend if direction of the current in a straight conductor were different ?Homework Equations ------The Attempt at a Solution...
37. ### Pleease explain uniformity of B in circular loop ?

Why is the magnetic flux density uniform at the center of the circular loop ?
38. ### Velocity and acceleration in a frictionless circular loop

This is a problem I encountered while studying/practicing for my upcoming MCAT exam: Homework Statement A 1kg block slides down a ramp and then around a circular loop of radius 10m. Assume that all surfaces are frictionless. 1)What is the minimum height of the ramp required so that...
39. ### Magnetic field lines in a current carrying circular loop

I wanted to ask that do each point of the current-carrying circular loop would create a magnetic field and hence the magnetic field lines? And if yes wouldn't the field lines produced by each point of the loop would intersect each other? I read somewhere that magnetic field lines never...
40. ### A current-carrying circular loop placed next to a long straight wire

Homework Statement A current-carrying circular loop of radius R is placed next to a long straight wire, as shown in the diagram below. The current in the straight wire points to the right and is of magnitude 3 A. see diagram...
41. ### Mistake with Biot Savart, B of a circular loop integral

I hope you don't mind if I'm a little liberal in your cute format. I'm looking for why method 1 does not equal method 2. 1. Homework Statement : Method 1--the "cute math" method. Alright, so... I have a circular loop of radius A, let's place it in the xy plane, with a steady current I...
42. ### What Is the Magnetic Field at the Axis of a Circular Loop?

Homework Statement As shown in the figure below, a circular loop of radius a = 0.1 m lies in the horizontal x-y plane with its center located at the origin, with steady current I = 2.0 A circulating in a counter-clockwise direction in the loop. The magnetic field strength B(0,0,z) at the...
43. ### Magnetic field of circular loop

Homework Statement Two small identical circular loops carrying equal currents are placed with the geometrical axis perpendicular to each other. Find the magnitude and direction at a point O at an equal distance x from their centers. Homework Equations Magnetic field of a current carrying...
44. ### Height of ramp given normal force in circular loop

Homework Statement The attachment shows the problem. The normal force at the top of the loop is 3 g's (as in g-force). Homework Equations PE = mgh KE = .5mv2 Fc = \frac{mv2}{r} PE + KE = PE' + KE' v = \sqrt{2gh} The Attempt at a Solution The normal force would be: 30 * mass...
45. ### How Is Torque Calculated in a Circular Coil within a Magnetic Field?

The maximum torue experienced by a circular, one-turn, coil in a 0.75T magnetic field is 8.4x10-4Nm. If the coil current is 3.7A, find the coil wire length. Homework Equations τ=Fr F=ILBsinθ ? r=L The Attempt at a Solution (8.4x10-4Nm)=[(3.7A)L(0.75T)sin90]L L=0.017m Can I do...
46. ### Single circular loop of wire filled with a uniform magnetic

Homework Statement The figure to the right shows a single circular loop of wire filled with a uniform magnetic field pointing into the page The radius of the loop is R = 1.75 cm. The magnitude of the magnetic field in the loop is changing according to B(t) = B0 exp{-t / 2.15sec} (a) what is the...
47. ### Magnetic Field Flux Through a Circular Loop Near an Infinite Wire

[b]1. A circular loop, (of radius 'a') is placed with its center at a distance 'r' from an infinitely long current carrying wire, (carrying current 'I'), in the same plane as that of the wire. For, a<r, find the flux of magnetic field through the loop. [b]2. Differential Flux=B.dA, whose...
48. ### Inductive reactance – Circular loop with N lambda standing wave

Has anyone come across, or may be able to point me in the direction of a method for evaluating the inductive reactance of a circular loop when the wavelength of the applied signal is significantly less than the conductor length of the loop - and more particularly when; A. The driven...
49. ### Inductive reactance – Circular loop with N lambda standing wave

Has anyone come across, or may be able to point me in the direction of a method for evaluating the inductive reactance of a circular loop when the wavelength of the applied signal is significantly less than the conductor length of the loop - and more particularly when; A. The driven wavelength...
50. ### Induced EMF and a circular loop of wire

Homework Statement A 25-turn circular loop of wire has a diameter of 1m. In 0.2 seconds it is flipped 180 degrees at a location where the magnitude of the Earth's magnetic field is 50 micro T. What is the emf generated in the loop?Homework Equations -(dB/dt)(A)=VThe Attempt at a Solution When I...