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1. ### Average back emf induced in coil

Homework Statement The coil in a loudspeaker has an inductance of L = 56uH (or 5.6 x 10^-5 H). To produce a sound frequency of 20 kHz, the current must oscillate between peak values of +2.2 A and -2.2 A in one half of a period. What average back emf is induced in the coil during this variation...
2. ### Earth's Magnetic Field Lab question

Homework Statement Using the Logger Pro Program plot a graph with the angle on the horizontal axis and the measured field on the vertical axis. The curve should have its maximum value at (theta) = S . where cos( theta - S) = cos(0) = 1. Use your graph to determine S, the declination at your...
3. ### Average back emf induced in coil

Homework Statement hey! I saw you've answered this question before... Hi, I would appreciate any help with the following: The coil in a loudspeaker has an inductance of L = 112 microH. To produce a sound of frequency 40kHz, the current must oscillate between peak values of + and - 4.4 A in...
4. ### Physics Lab Permability of free space

Homework Statement An ideal solenoid is expected to generate a dipole field that falls off quickly as you move away from the solenoid. The magnetic field at distance r along the axis of the solenoid is given by B = (Mo/ 2pie) (M/r^3) In this equation the parameter M is called the dipole...
5. ### Rate of Energy Transfer

Homework Statement It is fairly easy to produce a static magnetic field of 0.050T in the lab. If an EM wave could be produced with maximum magnetic field, Bo = 0.050T a) what would be the rate of energy transfer (W/m2) ? b) what would the corresponding maximum electric field be? Note * Air...
6. ### Counter emf generated in a motor at full speed

Homework Statement An electric motor draws 20.0 A of current when first switched on. The motors windings have a resistance of 5.0 ohm. Once the motor is up to full speed it draws only 4.4 A of current. Calculate the counter emf generated in the motor at full speed Homework Equations I = V/R...
7. ### What is the current in the loop

Homework Statement A piece of wire slides, without friction, along two similiar wires. The resistance per unit length of all wires is 0.350 ohms/m, and a constant magnetic field, B= 1.90T, points up, perpendicular to the loop. The distance between the parallel, fixed wires is 10.0cm. At the...
8. ### Path of electrons motion

Homework Statement A beam of electrons travels east at speed, v = 6.10x 10^6 m/s . It passes through a magnetic field , B = 0.450T , directed from top to bottom. Describe exactly the path of the electrons motion? Homework Equations The Attempt at a Solution The path of a charged particle...
9. ### Finding Dimensions of plates in Electric Field

Homework Statement The electric field between two circular plates of a capicator is changing at a rate of 1.5 x 10^6 V/m per Second. If the displacement current this instant is ID = 0.80 x 10^-8 A find the dimensions of the plates Homework Equations The Attempt at a Solution The capacitance...
10. ### What is the RMS magnetic field of light

Homework Statement A window, 1.0m by 1.0m receives 27J of energy, from sunlight, in one minute. What is the Rms magnetic field of the light striking the window. Homework Equations E = cB I = (ErmsBrms) / μo The Attempt at a Solution Not sure if those equations are right when solving this...
11. ### Physics lab formula question - help please

Homework Statement An ideal solenoid is expected to generate a dipole field that falls off quickly as you move away from the solenoid. The magnetic field at distance r along the axis of the solenoid is given by B = (Mo/ 2pie) (M/r^3) In this equation the parameter M is called the dipole moment...