Electromagnetic Induction TEST

2008-05-14 12:39:19

In the last few classes we have completed the curriculum for this course. We discussed and experimented with transformers, and practised problems.

The test on electromagnetic induction is written tomorrow, Th. May 15.

We will spend the remainder of classes on review and exam preparation.

electromagnetic induction

2008-05-06 15:57:23

The last few classes we have discussed and experimented with electromagnetic induction. The key idea of this last unit of the course (chapter8) is the following:

changing the magnetic field around a conductor, creates an electromotive force within it

We have discussed the tremendous significance of the discovery of the electric generator to our modern world. Faraday's law of induction and Lenz's law were discussed and demonstrated.

Homework assigned:

- complete exerc. 8.4 study 8.5 on 'back emf' => due tom, Wed, May 7

Magnetic forces review

2008-04-16 10:37:17

Today we discussed chapter 7 review questions, in preparation for the "Magnetic Forces" test on Monday, April 21.

Homework assigned:

complete PE sample problems => due Th, Apr. 17

mass spectrometry, motors

2008-04-16 10:28:56

Yesterday, we analyzed the results from our e/m experiment, and found that the experimental ratio was very close to the theoretical value. Then, we discussed applications of magnetic forces: themass spectrometer and the electric motor.

Homework assigned:

Complete p. 235 Exercises 1,2 CRQ on p. 237 1-4 => due Wed, Apr. 16

current balance and e/m experiments

2008-04-11 12:24:23

Thursday, experiments were completed with the current balance, and with the cathode ray tube. Using the first set-up, we determined how the magnetic force depends on the current and the length of wire in the magnetic field. In a repeat of Thompson's historical experiment, we determined the charge-to-mass ratio of an electron by deflecting an electron beam into a circular path, using a magnetic field. We measured the current through the Helmholtz coils, the accelerating voltage and the radius of the circular path. In the coming class, we will use these data to calculate the e/m ratio.

Homework assigned:

Complete a Lab Report on the current balanve experiments => due Mon, Apr. 14

force on a current-carrying wire

2008-04-09 20:25:01

Today we reviewed the key idea of chapter 7: moving charges experience a force in a magnetic force. We utilize this magnetic force in moving electrons over a phosphor-coated screen, in a TV. We also use it to turn a coil of wires in an electric motor.

Tomorrow we will determine how the magnitude of the magnetic force depends on: the current through the wire, the length of the wire segment, and the magnetic field strength.

Homework assigned:

- complete Exercises 1-5 on p. 227 => due tomorrow, Th, Apr 10

"How Attractive"

2008-04-08 12:49:35

Today we we determined - in a series of experiments - how the magnetic field strength of a solenoid depends on the current and the solenoid length.

Homework assigned:

- complete Analyze and Synthesize questions on Lab hand-out => due tomorrow - Wed, Apr 9

magnetic field strength

2008-04-07 16:00:54

Today we reviewed the formula for determining the magnetic force on a moving charge in a magnetic field, and discussed themeasurement of magnetic field strength.

We prepared for tomorrow's lab activity: "how does the magnetic field strength of a solenoid depend on the current?"

Homework assigned:

Study 7.4, 7.5 complete exercises on p. 221 => due tomorrow, Tu Apr. 8

magnetic force

2008-04-03 10:04:54

Today we investigated the force on charged particles moving in a magnetic field. Experimenting with the cathode ray tube and a permanent magnet, we confirmed the right hand motor rule for determining the magnetic force direction.

We also reviewed the right rules for the magnetic field direction of current-carrying wires and solenoids.

Homework assigned:

Study 7.3 complete Exerc. 1-3 on p. 220 => due Mon, Apr. 7th

magnetism

2008-04-02 16:56:01

On Tuesday we reviewed last term's circuits test. Then -throughhands-on activities -basic concepts of magnetism (such as poles, force, and field) were reviewed.

Homework assigned:

Complete Exercises 1,2 on p.212 => due Th, Apr. 3

kirchhoff's laws

2008-03-12 16:02:33

Tuesday, we completed the experiments, confirming Kirchhoff's current and voltage laws for series and parallel circuits.

Today (Wednesday), we practised solving problems involving circuits.

Thursday (tomorrow), Mar. 13 there will be a quiz on chapter 6 Resistor circuits

Homework assigned:

study a selection of CRQ and Test Yourself to prepare for tomorrow's quiz.

Internal resistance and Kirchhoff's laws

2008-03-06 12:18:16

Today we designed and carried out an experiment to determine the internal resistance of a cell.

Then we discussed voltage, current and (equivalent) resistance in series and parallel circuits, in connection toKirchhoff's Laws. We started an experiment to confirm Kirchhoff's Laws for a series circuit.

Homework assigned:

summarize 6.8, 6.9 => due Tu, Mar 11

Joule's Law and internal resistance

2008-03-05 15:14:40

Today we evaluated the Ohm's Law experiment, discussed Joule's Law, and explainedyesterday'smeasurements of terminal voltage as a function of current.

Homework assigned:

p. 184: Exercises 1-5 => due tomorrow, Th. Mar 6

ohm's law and emf

2008-03-04 13:09:25

We discussed how a rechargeable battery works.

Then we briefly reviewed Ohm's law and discussedelectromotive force.We conducted experiments in order to: (1) confirm that current is directly proportional to voltage, (2) determine the resistance of the carbon resistor, and (3) show that the voltage supplied by a cell is dependent on how much current is flowing through it.

Homework assigned:

Short lab report on experiments conducted Exerc. 1-3 on p. 181 => due tomorrow - Wed, Mar. 5

resistor circuits 1

2008-02-28 12:09:20

We discussed the electrostatics test, then started chapter 6: "Resistor Circuits".

Cells and EMF were discussed.Then thevoltage, current, and resistance in a electric circuit were compared to the pressure, flow rate, and tube resistance of a water pump system. Finally, the calculation of electron drift velocity was demonstrated.

http://hyperphysics.phy-astr.gsu.edu/hbase/electric/watcir.html

Homework assigned:

p.180: Exercises 1-6

Assignments NHI:

-

Electrostatics test

2008-02-26 13:06:12

Today A. wrote his test on electrostatics. From today onwards, any homework assignments will be posted here.

Chapters 3 and 4 TEST - Jan 31

2008-01-20 14:51:42

The Chapters 3 and 4 TEST will be written on Thursday, January 31.

This test covers the subunits ofDynamics, Momentum, Energy, Circular motion, and Gravity.

Main skills and concepts to review:

3.1 Dynamics (in 2 dimensions):

- applying Newton's laws to solve problems involving mass, forces, acceleration, velocity, distance.

3.2 and 3.3 Momentum, impulse, Conservation of momentum (in 2 Dimensions):

- applying momentum, impeulse and conservation of momentum to solve problems involving mass, velocity, force.

3.4 -3.10 Work, Kinetic Energy, Potential Energy, Conservation of Energy, Power:

- applying concepts of work, energy, conservation of energy, and power to solve problems involving mass, velocity, height, distance, extension, energy, work, and power

4.1 Circular motion, centripetal acceleration, centripetal force:

- applying concepts of centripetal acceleration and force to solve problems involving period, frequency, velocity, forces, mass, radius, centripetal acceleration and centripetal force.

4.2, 4.4-4.9 Universal gravitation, free fall, gravitational field strength, weightlessness, gravitational potential energy:

- applying concepts of universal gravitation, gravitational field strength, and gravitational potential energy to solve problems involving mass, radius, forces, orbital velocity, escape velocity, gravitational field strength, and energy.