Induced Currents?

Question

1. currents circulate in a piece of metal that is pulled through a magnetic field what are they called? (is it the solonoid??)

2. A c.r.o (cathode ray osc.) is set to 5V/cm. if height of wave from peak to peak is 5cm. what is V peak and V r.m.s (root means squared)

3. what is a flux linkage?

4. an A.C power outlet is labelled 240V what is Vpeak and Vr.m.s

5. an oscilloscope has a grid of 10div x 10 div. if time base is set at 3ms/div, how many times does the beam scan the screen per minute? what is the frequency?


thnx!!!

Answer 1

1. eddy currents

2. V peak = 5 x 5 = 25
V rms = 25 / sqrt(2)
= 17.7 V

3. It is the magnetic flux density x the perpendicular area of the conductor.
It is the amount of magnetic flux connected to a conductor in a magnetic field.

4. V rms = 240 V
V peak = sqrt(2) x 240
= 339 V

5. 10 div horizontally means that beam sweeps screen in 3 x 10
= 30 ms
In one second the number of sweeps = 1 / 0.030
= 33.3
This is the frequency => 33.3 Hz

In one minute, number of scans = 60 x 33.3
= 2000

Answer 2

Three of your questions don't have enough information for a good answer.
1. Hans got it; eddy current is correct.
2. If the wave is symmetrical about zero Vpeak = Vpeaktopeak/2; if not there are two unequal Vpeak values that add to Vpeaktopeak.. Vrms only = sqrt(2)*Vpeak if it's a sine wave.
3. Hans's answer is good.
4. Depends on whether it's 240V single-phase or 3-phase. Hans's answer applies to single-phase. If 3-phase, the voltage between any two phases is sqrt(3) * the phase-to-neutral voltage. (In the U.S., the phase-to-neutral voltage is usually set to 120VRMS so the phase-to-phase voltage is 208VRMS; Vpeak will be sqrt(2) * VRMS no matter what; see ref.).
5. There's a retrace time which is accounted for either by slowing down the scan repetition rate or by reducing the amount of time actually displayed. Also if the scan is synced to some feature of the signal it could be slowed down more.

Answer 3

1) Solenoid
2) 5V Vpeak and 3.53V Vrms
3) Btwn two conductig coils, flux of one coil affects another coil
4) 240V is line voltage its p2p voltage is 240/root(3)
and vrms is again divide it by root(2)