Take Test: Homework - Magnetic Circuits * Test Information Description Instructions Multiple Attempts This test allows 3 attempts. This is attempt number 1. Force Completion This test can be saved and resumed later. Your answers are saved automatically. * Question Completion Status: QUESTION 1 Which of the following is not true of magnetic lines of flux? The density increases with increasing distance from the poles. They seek the path of least resistance between opposite magnetic poles. O They never cross one another. O They all have the same strength. QUESTION 2 Given the choice, why do magnetic lines of flux prefer to travel through iron instead of copper? O Because there is greater electron density in iron than in copper. Because iron has a much lower reluctance due to its magnetic properties. Because iron is heavier than copper, resulting in a greater flux density. O Because iron is one of the few materials that has all of its electrons spinning in a counterclockwise direction. QUESTION 3 Where do magnetic fields exist? Check all that apply. In the vicinity of an electrical wire carrying current. In the vicinity of a permanent magnet In the vicinity of any metal, including coins and forks. O In the area around fermenting fruit if the temperature is greater than 95 degrees.QUESTION 4 Why is it more difficult to wiretap a fiber optic line than an electrical wire? O As fibers are made of glass and carry light, they produce no magnetic fields when carrying information. The magnetic fields produced by fiber optic lines cannot be sensed except by a special machine known as a cortitron. O The glass in a fiber optic line will likely break when its magnetic field is sensed. O Fiber optics contain special armatures that dispel any attempt to produce disantasia QUESTION 5 Two electrical wires carrying information can affect one another, possibly making the data invalid. This effect is known as O EMI (electromagnetic interference) O MFD (magnetic field disturbance O EDI (electrical disturbance and interference) O MI (magnetomotive interference) QUESTION 6 Find the number of turns necessary to establish a magnetic flux of @ = 3.64 x 10 * Wb in the series magnetic circuit below. 45 cm Cast iron 27 cm 1 10 cm 30 cm 1=5A O 510 O 740 1080 O 1460QUESTION 7 Find the value of I to establish a magnetic flux of @ = 9.6 x 10-3 Wb in the series magnetic circuit below. myTOUG VI VUIL VEIW. 70 cm Cast steel -23 cm 40 cm Air gap = 3 mm For an air gap, H, = B /(411 x 10.?) N = O 4.22 A O 7.39 A O 11.65 A O 13.87 A QUESTION 8 IndyTOUG UI VUIL VEIW. Sheet steel radius = 70 cm N = 2000 Air gap = 2 mm For an air gap. H. = B /(411 x 10.?) `diameter = 15 cm Find the value of I to establish a magnetic flux of @ = 2.37 x 10"-Wb in the series magnetic circuit below. O 2.61 A O 4.07 A O 7.35 A O 11.46 AQUESTION 9 Find the value of I to establish a magnetic flux of @ = 7.26 x 10- Wb in the series magnetic circuit below. magnetic circuit below. 77 cm Cast iron Cast steel I 11 cm 55 cm N = 1500 0.87 A O 1.55 A O 2.78 A 4.67 A QUESTION 10 Find the value of I to establish a magnetic flux of = 1.18 x 10- Wb in the series magnetic circuit below. Cast iron radius = 1 foot N - 1200 Air gap = 1/B inch For an air gap, H, = 8 /(401 x 10?) `diameter = 2 inches O 1.38 A 3.36 A 5.05 A O 8.32 A