Induced emf Definition and 245 Threads

Hi! I read this article about Faraday's law, which states, that the emf will be always negative, by the formula, is this http://hyperphysics.phy-astr.gsu.edu/hbase/electric/farlaw.html"

Homework Statement The solenoid has N turns of wire around a cylinder. The radius of the cylinder is "a" and length is "b." THe current of the solenoid varies as I(t)= I_{0}(1 - e^-\alphat) . I_{0} and \alpha are positive constants. Around the solenoid is a square loop of wire with side...

Homework Statement A circular loop of wire can be used as a radio antenna. If an antenna with a diameter of 20.0 cm is located a distance of 2.40 km away from a from a source with a total power of 45.0 kW at a frequency of 101 MHz, what is the maximum emf induced in the loop? (Assume that the...

Homework Statement If the current is increasing at a rate of 0.1 A/sec what would the induced emf in a loop of 0.5 m be? Homework Equations I = \frac{|emf|}{R} emf = - \frac{d}{dt} B A cos(\theta) I'm obviously missing an equation or something. Some guidance would be much...

Hi guys - Here's the problem I'm stuck on: In a physics laboratory experiment, a coil with 160 turns enclosing an area of 13.7 (cm^2) is rotated during the time interval 4.60×10−2(s) from a position in which its plane is perpendicular to Earth's magnetic field to one in which its plane...

well iwas going through the standard example that is there is a uniform magnetic field in aregion going into the palne and ther is a rectangular 'loop' with one side which can slide on metallic rods with constant speed v and the the relation \epsilon=BLv well the example is (almost) here well...

Homework Statement Given: u_0 = 1.25664e-6 A 2 m long large coil with a radius of 14.6 cm and 320 turns surrounds a 4.2 m long solenoid with a radius of 4.6 cm and 7700 turns. The current in the solenoid changes as I = I_0 sin (2pi*f*t) where I_0= 30 A and f=60 Hz.Inside solenoid has...

Homework Statement "A square loop of wire is held in a uniform magnetic field of .24 T directed perpendicular to the plane of the loop. The length of each side of the square is decreasing at a constant ratee of 5.0 cm/s. What is the emf induced in the loop when the length 12 cm...

A 11.8m long steel beam is accidentally dropped by a construction crane from a height of 8.62m. The horizontal component of the Earth's magnetic field over the region is 16.7μT. What is the induced emf in the beam just before impact with the Earth, assuming its long dimension remains in a...

Homework Statement In Figure 30-52 (see attached), a metal rod is forced to move with constant velocity v along two parallel metal rails, connected with a strip of metal at one end. A magnetic field B = 0.370 T points out of the page. (a) If the rails are separated by 26.0 cm and the...

A circular conducting coil with radius 2.61 cm is placed in a uniform magnetic field of 0.827 T with the plane of the coil perpendicular to the magnetic field. The coil is rotated 180° about the axis in 0.222 s. (a) What is the average induced emf in the coil during this rotation? (b) If the...

Homework Statement http://www.jyu.fi/kastdk/olympiads/2005/Th2.pdf http://www.jyu.fi/kastdk/olympiads/2005/Th2%20Solution.pdf (Question 3) My first doubt is why the magnetic field at the center of the coil is: |\vec B|=\frac{\mu_0 NI}{2a} and not |\vec B|=\mu_0 nI, where n=N/l...

Homework Statement A car with a vertical radio antenna 85cm long drives due east 25 m/s. The Earth's magnetic field at this location has a magnitude of 5.9 * 10-5 T and points northward, 72 degrees below the horizontal. a) Is the top or the bottom of the antenna at the higher potential? b)...

Homework Statement Assume the field inside the larger coil (.075m Radius, 1200 loops), reaches the maximum value when the smaller solenoid, (.05m radius, 1200 loops), is halfway inserted. with what constant velocity must the smaller solenoid be inserted to induce 2.3V in the larger solenoid...

Homework Statement The 2-cm (radius) current loop shown in the figure is changing from θ1 = 11 degrees to θ2 = 66 degrees in a magnetic field 2 T in 0.5 seconds. What is the magnitude of the induced emf to the nearest hundredth of a millivolt. The wire in Problem 2 has a thickness of 1.04...

Homework Statement A car with a vertical radio antenna 75 cm long drives due west at 23 m/s. The Earth's magnetic field at this location has a magnitude of 5.9 10-5 T and points northward, 74° below the horizontal. Find the induced emf between the ends of the antenna. Homework Equations...

A car with a vertical radio antenna 75 cm long drives due east at 29 m/s. The Earth's magnetic field at this location has a magnitude of 5.9* 10^-5 T and points northward, 72° below the horizontal. (b) Find the induced emf between the ends of the antenna. Relevant Equations: E = BVL...

induced emf! Hello, I am studying magnetic induction, induced emf, and faraday's law, that sort of thing. My book gives an example where the magnitude of a B-field is increasing at constant rate through an axis of a circular coil with N number of turns and a certain radius r, find the...

In a physics laboratory experiment, a coil with 210 turns enclosing an area of 12.7 cm^2 is rotated during the time interval 3.70 \cdot 10^{−2} sfrom a position in which its plane is perpendicular to Earth's magnetic field to one in which its plane is parallel to the field. The magnitude of...

average emf is it same as induced emf?? Q: a 25-turn circular coil of wire has diameter 1.00m. it is placed with its axis along the direction of the earth'smagneticfield of 50.o uT, and then in 0.200s it is flipped 180 degrees. an average emf of what magnitude is generated in the coil? N =...

This problem is difficult to describe, so I'll post a picture. http://img71.imageshack.us/my.php?image=pic1ik.gif The figure above shows a rod of length L caused to move at a constant speed v along horizontal conducting rails. The magnetic field B (the magnitude and direction of which are...

A 1 m long large coil with a radius of 15.2 cm and 280 turns surrounds a 7.6 m long solenoid with a radius of 5.2 cm and 3200 turns. The current in the solenoid changes as I=I_0 sin (2\pi f t) where I_0= 30 A and f=60 Hz.Inside solenoid has 3200 turns and outside coil has 3200 turns. The...

A 5.97 m long steel beam is accidentally dropped by a construction crane from a height of 6.82 m. The horizontal component of the Earth's magnetic field over the region is 12.2 \mu T. The acceleration of gravity is 9.8 m/s^2. What is the induced emf in the beam just before impact with the Earth...

A magnetic field with the time dependence shown in Figure 23-38 is at right angles to a 181 turn circular coil with a diameter of 3.91 cm. What is the induced emf in the coil at each of the following times? (a) t = 2.50 ms 0 V (b) t = 7.50 ms (c) t = 15.0 ms...

What would be the change of the induced emf in the secondary coil of a two coil system ( without ferromagnetic core ) if both the amplitude and the frequency of the current in the primary coil would double?: emf would stay the same emf would be halved emf would be 4 times larger...

1] A square loop of wire, with sides of length 'a' lies in the first quadrant of the xy-plane, with one corner at the origin. In this region there is a non-uniform time-dependent magnetic field \vec B (y,t) = ky^3t^2\hat z. Find the induced emf in the loop.I applied the flux rule here...

If we have a loop with radius 12 cm that lies in a uniform magnetic field of 1.5T. The magnetic field is in the positive z direction and the loop lies in the horizontal xy-plane. Now if the loop is removed from the field in a time interval of 2.0x10^-3 s what will the average induced emf be...

I'm reposting this because my homework is due in an hour and I still have not received help on how to solve this. I understand now that the the loop is equal to one. But could someone be generous enough to explain to me what the area is on problem 2 and 3 and why .503 is wrong for question 1...

I'm having a lot of trouble with the following questions. I was wondering if someone could steer me in the right direction and tell me what I'm doing wrong. I suppose my biggest problem is I don't understand how to do these without knowing the number of turns in the coil. Here's what I've done...

Suppose i have a wooden ring and a time varying magnetic field is passed through it. Then will there be induced emf.

Here is the problem: A coil containing 590 turns with radius 3.85 cm, is placed in a uniform magnetic field that varies with time according to B=( 1.20×10−2 T\s)t+( 3.40×10−5 T\s^4)t^4. The coil is connected to a resistor of resistance 690 Ohms, and its plane is perpendicular to the magnetic...

Can someone check my equation for flux. Thanks A rectangular loop in the z-y plane is situated at t = 0 at the points (x=1,z=0), (x=1,z=5), (x=4,z=5), and (x=4,z=0). The rod of the loop with end points (x=4,z=0), and (x=4,z=5) is moving in the x-direction with a velocity v=5\vec{i}m/s while...

Electromagnetism -- induced EMF Please help :) I'm just trying to grasp the whole ... induced EMF concept ... please, anyone?! Also ... breaking the field lines?

Hey, I'm in a high school AP class and am stuck! Can anyone help me with this problem concerning induced emf? I would surely appreciate it. There is a loop of wire, shaped like a square. Each side is 20 cm long. There is a magnetic field directed into the page. What would be the way of...

Hey, I'm in a high school AP class and am stuck! Can anyone help me with this problem concerning induced emf? I would surely appreciate it. There is a loop of wire, shaped like a square. Each side is 20 cm long. There is a magnetic field directed into the page. What would be the way of...

A 14.2m long steel beam is accidentally dropped by a construction crane from a height of 9.53m. The horizontal component of the EArth's magnetic field over the region is 16.4 uT. What is the induced Emf in the beam just before impact with the earth, assuming its long dimension remains in a...

A circular loop of radius 17 cm is located in the plane of the paper inside a homogeneous magnetic field of 0.7 T pointing into the paper. It is connected in series with a resistor of 131 ohm. The magnetic field is now increased at a constant rate by a factor of 2.2 in 15 s. Calculate the...

A 7.2 cm diameter loop of wire is initially oriented perpendicular to a 1.3 T magnetic field. It is rotated so that its plane is parallel to the field direction in .20 s. What is the average induced emf in the loop? A = πr2 A = π*.001 = .004 m ФB = BA = (1.3T)(.004m) = 5.2E-3 Wb...

Here is a bonus question that I was given yesterday. I am completely at a loss of what to do. Any suggestions? A conducting loop with a half circle of radius r=0.20m and 3 straight sections. The half circle lies in a uniform field B that is directed out of the page. The magnitude of B as a...

Hello, I don't know if you will find this question silly or not because I know it shouldn't be that hard but for some reason I keep getting it wrong. Here it is: A square copper loop, with sides of length 10.4 cm, is located in a region of changing magnetic field. The direction of the...

I was wondering just how possible it is to "steal" electricity by inducing an EMF near the transmission cable? Does the electric company have ways to detect this or have counter-measures set up? How big would the wire need to be and made of what material? I am very interested in how all of...

In physics class today, we did a project that I don't quite understand. We layed a small 50-turn coil flat on the table and held a magnet in a vertical position near the coil. We had the Galvanometer hooked up to make a clockwise current. The class then moved the magnet close to the coil and...

A 5.56m long steel beam is accidentally dropped by a construction crane from a height of 3.97m. The horizontal component of the Earth's magnetic field over the region is 28.4e-6T. Acceleration of gravity is 9.8 m/s^2. What is the induced emf in the beam just before impact with the Earth...

Ok, so here's the problem: Induced EMF A 5.80 cm diameter wire coil is initially oriented so that its plane is perpendicular to a magnetic field of 0.770 T pointing up. During the course of 0.140 s, the field is changed to one of 0.240 T pointing down. What is the average induced emf in the...

One more problem that's causing me grief: A square loop of wire, b meters on a side, moves with constant velocity v (m/sec) toward the right in the plane of a long straight wire carrying a steady current I amperes. Calculate the emf induced in the loop when the side of the loop nearest the...