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? O The density increases with increasing distance from the poles. O 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. O 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. O In the vicinity of a permanent magnet. O 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. O 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 277 cm T 10 cm 30 cm 1=5A 0 510 O 740 O 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. 70 cm 278 cm Cast steel 18 cm 40 cm Air gap = 3 mm For an air gap, H, = B /(411 x 10.?) N= 750 O 4.22 A O 7.39 A O 11.65 A O 13.87 A QUESTION 8 MaybeUG UI VUIL VEIW. Sheet steel radius = 70 cm N = 2000 Air gap = 2 mm For an air gap. H, = B /(411 x 10.7) `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 2111 cm Cast steel T.11 cm 55 cm N = 1500 O 0.67 A O 1.55 A O 2.78 A O 4.67 A QUESTION 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, = 0,/(401 x 10?) `diameter = 2 inches O 1.38 A O 3.36 A O 5.05 A O 8.32 A