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# EMF

### Electromagnetics: Bar Magnet, Loop of Wire and Induced EMF

Consider a bar magnet and a loop of wire. We will examine the interactions of these two objects and the resulting induced EMF. Which of the following statements are true about this case? -if the bar magnet is moved through the loop (North pole first), there will be an induced EMF in the loop -if the bar magnet is moved

### What Will Not Induce an EMF in a Coil of Wire?

Which of the following cases will NOT induce an EMF in a coil of wire? (True/False problem) 1) By increasing the magnetic field in which a wire coil sits. 2) By rotating a coil of wire counter-clockwise in a constant magnetic field. 3) By pushing a bar magnet into a coil of wire. 4) By decreasing the area of a coil

### Calculate EMF and Internal Resistance: Battery Problem

Part 1: A battery has an emf E and an internal resistance r. When the battery is connected to a 28.0 W resistor, the current through the battery is 0.604 A. When the battery is connected to a 53.1 W resistor, the current is 0.499 A. Calculate the emf of the battery (in V). Part 2: Calculate its internal resistance (in o

### Electromagnetic Induction: Induced current in rotating disk

Assume a rotating (angular velocity W) metal disk located in the x-y plane with a constant magnetic field B perpendicular to the disk. A circuit containing a resistor is connected between the spindle (axis) the disk rotates on and a spring contact that is in contact with the outer edge of the disk. What is the current flo

### Voltage Inside a Magnetic Field

The square wire in below figure has a side of 10 cm and is in a magnetic field of strength 0.18 T. If the magnetic field decreases at a rate of 0.1 T/s, find the reading of the voltage meter. Also the field is coming out of page.

### Elements of Crystallizes in Body-Centered Cubic Lattice

Chapter 11 5. An element crystallizes in a body-centered cubic lattice. The edge of the unit cell is 2.98 , and the density of the crystal is 8.99 . Calculate the atomic weight of the element. 9. Calculate the minimum number of grams of propane, , that must be combusted to provide the energy necessary to convert 5.70

### Magnitude of the emf induced between the two sides of the shark

A scalloped hammerhead shark swims at a steady speed of 1.5 m/s with its 85 cm wide head perpendicular to the earth's 50 (unit is "mu T" )magnetic field. What is the magnitude of the emf induced between the two sides of the shark's head?

### Electro Magnetic Induction: Motional EMF Induced in Wire

A potential difference of 0.050V is developed across the 10 cm long wire as it moves through a magnetic field at 5.0 m/s. The magnetic field is perpendicular to the axis of the wire. What are the direction and strength of the magnetic field?

### Electro-Magnetic Induction: Cause of Induced Current

What is actually causing the force on the charges of the conducting plate if indeed the current is present when the magnet rotates with the conductor. If a magnet and adjacent wire move together linearly, a current will not be created since there could not be a current/voltage in the reference frame of the magnet-wire where

### Equations for Currents, Loops, and Torques

What equations are needed to solve this problem? How would the equations change if it was a circular loop? a) A square loop of the side length (a) carries a current (i) in the clockwise direction. The loop is placed in a magnetic field at an angle of 45 degrees to it (you can rotate the loop about the field as you like to ma

### Magnetic Field with EMF

A circular loop in the plane of the screen lies in a 0.89 T magnetic field pointing into the screen. The loop's diameter changes from 19.0 cm to 6.0 cm in 0.50 s. What is the magnitude of the average induced emf? mV If the coil resistance is 2.5 , what is the average induced current? mA

### Toroidal Solenoid: Determination of self inductance, induced emf, potential of induced emf

Please help answer the following problems. Provide step by step calculations. A toroidal solenoid has 550 turns, cross- sectional area 6.7 square cm, and a mean radius of 4.8 cm. A) Calculate the coil's self-inductance. B) If the current decreases uniformly from 5A to 2A in 3ms, calculate the self induced emf in the co

### Inductance of a Coil

One of the coils we use in class has 157 turns in 18 cm and a cross section area of 5.0 * 10^-3 m^2. (a) What is its inductance L, and (b) What self-induced emf will it produce at 100 ms if the current through it changes as shown in this graph?

### Electrical Physics: Parallel Resistance, Circuit Resistance

A resistor R1 is connected in series with a parallel connection of resistors R2 and R3. The combination is connected across a battery of emf, ¦Î, with internal resistance, r. If R1 = 3.00¦¸, R2 = 3.00¦¸, R3 = 6.00¦¸, ¦Î = 6.00 V, and I = 1.00A, find Rp, the equivalent parallel resistance, Rt the total circuit resistanc

### Charge on Capacitor in Varying Situations

See the attached file. In the circuit shown in the figure (Intro 1 figure) C= 5.90uF , E=28.0V, and the emf has negligible resistance. Initially the capacitor is uncharged and the switch S is in position 1. The switch is then moved to position 2, so that the capacitor begins to charge. 1) What will be the charge on the ca

### 3 questions on electric circuits with many components

1.) What is the potential difference Vad in the circuit of the figure? (Part A 1 figure) 2.) What is the terminal voltage of the 4.00-V battery? 3.)A battery with emf 10.30V and internal resistance 0.50ohms is inserted in the circuit at d, with its negative terminal connected to the negative terminal of the 8.00-V batt

### Circuits Diagram Solutions

The circuit shown in the figure (Intro 1 figure) contains two batteries, each with an emf and an internal resistance, and two resistors. Please see the attached page. 1.) Find the magnitude of the current in the circuit. Express your answer using two significant figures. 2.) Find the direction of the current in the cir

A magnet is plunged into and out of a coil of wire 2 times per second. Thus induces 5 volts. If the rate of motion changes so that the magnet is plunged in and out 6 times per second, what will be the new induced voltage? If the number of coils in the wire is doubled from 100 to 200, and the original rate of 2 times per seco

### Set of multiple choice questions on magnetic fields.

2. A coil of wire carries current I flowing clockwise as shown in the figure. The outer circle is the current loop. If the observer could "see" the magnetic field inside this arrangement of loops, how would it appear? (see attached file for diagrams) 3. A conducting loop of wire is placed in a magnetic field that is norm

### the direction and the magnitude of the current in the loop

The loop in the figure below is being pushed into the 0.20 T magnetic field at 50 m/s. The resistance of the loop is 0.10 ohms and its width (d) is 4.6 cm. What are the direction and the magnitude of the current in the loop. Attached is the diagram.

### Magnetic force of a current carrying cross bar placed in a magnetic field. To determine instantaneous magnitude of acceleration, steady state speed and current flowing through it.

A schematic 'rail gun motor' is shown in figure 1 (see attachment). Two horizontal parallel rails are a distance L apart and are joined at one end by a voltage source producing a fixed voltage Vo. A crossbar of mass m completes the circuit. The cross bar is free to slide on the rails, always remaining perpendicular to them. All

### Simple electrical circuit

In the circuit shown in the figure both batteries have insignificant internal resistance and the idealized ammeter reads 1.50 A in the direction shown. What is the emf V of the battery and is the polarity in the correct direction?

### Given a circuit and find dissipated as thermal energy in the battery.

1. A wire of resistance 5.0 ohm is connected to a battery whose emf is 2.0V and whose potential resistance is 1.0 ohm. In 2.0min, how much energy is (a) transferred from chemical form in the battery, (b) dissipated as thermal energy in the wire, and (c) dissipated as thermal energy in the battery? 2.The starting motor of a ca

### Thevenin's Theorem

a. Use Thevenin's theorem to calculate an equivalent e.m.f and resistance for the circuit contained in the box to the left of terminals A and B (steady state conditions) b. Sketch the complete Thevenin circuit plus load and calculate the current through the 10 resistor.

### Electromagnetic induction and the Lorentz force

1. An infinitely long, straight wire carries a constant current I along the z-axis. A rectangular loop of conducting wire (dimensions = a x b) is located in a radical plane at a distance x from the wire, as shown. (see the attached file for the diagram) (a) Find the flux of the magnetic-field B through the loop. (b) If

### Batteries and Hydrogen

1. The lead acid battery used in cars uses the reaction of Pb + PbO2 + 2H+ + 2HSO4- ---> 2PbSO4 + 2H2O and has a cell potential of 2.046 volts. How are 6 volt and 12 volt batteries produced for cars? a. The pH is made very acidic. b. 3 or 6 cells are connected together to increase the voltage c. The concentrati

### Introduction to Decision Making

You are observing a meeting between Milhouse (one of your co-workers) and a salesman who is trying to sell an additional part to a machine that your company recently purchased. The salesman is well into his routine, and has already gotten your co-worker to admit that a quality product is of utmost importance to the future of the

### Looking for help with image formats

What kinds of image formats are available for putting onto the Internet? What different file formats that are available to me? What are the major advantages and disadvantages of each one?

### Induced emf in loop.

The current in the long straight wire AB of the figure is upward and is increasing steadily at a rate of di/dt. 1. what is the total flux in through the loop? 2. what is the induced emf in the loop?

### Induced EMF in a circular loop

A circular loop of flexible iron wire has an initial circumference of 165.0 cm, but its circumference is decreasing at a constant rate of 12.0 cm/s due to a tangential pull on the wire. The loop is in a constant uniform magnetic field of magnitude 0.500 T, which is oriented perpendicular to the plane of the loop. Find the in