Friday, June 3, 2011

Electromagnetism applications?

If anyone could help me out with any of these 15 questions it would really appreciated





1. A small bar magnet is hidden inside a tennis ball. Describe at least 2 different experiments you could do to find the location of the N-pole and the S-pole of the magnet inside the ball without using another magnetic.


2. A room contains a strong, uniform magnetic field. A loop of fine wire in the room has current flowing through it. You rotate the loop until there is no tendency for it to rotate as a result of the magnetic field. What is the direction of the magnetic field relative to the plane of the loop? How does this situation apply to the operation of motors?


3. Research superconductors. Iron, nickel, and cobalt are electrical conductors. So are superconductors. But do they behave the same way in magnetic fields? Explain.


4. A magnet can attract a piece of iron that is not a permanent magnet. A charged strip of acetate can attract an uncharged insulator. Describe the microscopic effects that make these two similar.


5. An electric field can exert a force on a charged particle. A magnetic field can exert a force on a charged particle as well. Can either force change the kinetic energy of the particle? Explain.


6. Is the magnetic force the Earth exerts on a compass needle greater than, equal to, or less that the force the compass needle exerts on Earth? Explain.


7. Find a diagram of the magnetic field lines around the Earth and include it in your report. Observe the density of the lines and explain where the magnetic field is strongest, the poles or the equator. Now, use this knowledge to explain at what location would the circular paths followed by charged particles have larger radii.


8. You are lost in the woods but you have a compass. Unfortunately, the red paint marking the N-pole of the compass has worn off. You do have a flashlight with a battery and a length of wire. Describe how you could identify the N-pole.


9. Each electron in a piece of iron is like a tiny magnet. The iron, however, is not a magnet. Explain. Use this concept to answer the question: If you break a magnet in two, will you have a north-pole piece and a south-pole piece?


10. A strong current is suddenly switched on in a wire. No force acts on it. Can you conclude that there is no magnetic field at the location of the wire? Explain.


11. Research alternating current. The direction of AC voltage changes 120 times each second. Does that mean a device connected to an AC voltage alternately delivers and accepts energy?


12. A transformer is connected to a battery through an on/off switch. The secondary circuit contains a light bulb. Which of these statements best describes when the light bulb will be lit? a) as long as the switch is turned on; b) only the moment the switch is turned on; c) only the moment the switch is turned off. EXPLAIN.


13. Thomas Edison proposed distributing electrical energy using constant voltages (DC). George Westinghouse proposed using AC. Which was chosen and why is it a very economical choice after all?


14. When you drop a magnet (N-pole first) down a copper tube it seems to float down. Diagram the set up. EXPLAIN using the concepts of induction, Lenz鈥檚 Law, Conservation of Energy and your right-hand rules.


15. A bicycle鈥檚 headlight is powered by a generator that rubs against one of the wheels. Is the bike harder to pedal when the generator is lighting the lamp? Explain.|||Lol i got the same worksheet, I%26#039;m doing it right now so i don%26#039;t have much time to go into greater explanation.


1. Use compass/sprinkle iron fillings on tennis ball


5. Electric field-Yes, force opposes motion Magnetic field-No, force is perpendicular to motion


6. The same, Newton%26#039;s third law-


8. line the wire with compass, make current with battery, use right hand rule to see which way the magnetic field of the wire goes, compass north should point that way


10. Yes, if there was, the wire would move


13. http://en.wikipedia.org/wiki/War_of_Curr鈥?/a>


does your worksheet only say to do 10 out of the 15?