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Unformatted text preview: wilson (kw22588) – HW10 – Mackie – (20224) 1 This printout should have 12 questions. Multiplechoice questions may continue on the next column or page – find all choices before answering. 001 10.0 points A solenoid 6 . 3 cm in radius and 40 m in length has 13800 uniformly spaced turns and carries a current of 8 . 8 A. Consider a plane circular surface of radius 3 . 1 cm located at the center of the solenoid with its axis coincident with the axis of the solenoid. What is the magnetic flux Φ through this circular surface?(1 Wb = 1 T m 2 ) Correct answer: 1 . 15182 × 10 − 5 Wb. Explanation: Let : ℓ = 40 m , N = 13800 , I = 8 . 8 A , and r = 3 . 1 cm = 0 . 031 m . Basic Concepts: B = μ N I l I = μ n I Φ B = integraldisplay vector B · d vector A The magnetic field in the solenoid is given by B = μ I N ℓ Call A the area of the plane circular surface. The the magnetic flux through this surface is Φ = B A = μ I N ℓ π r 2 = μ (8 . 8 A)(13800) 40 m π (0 . 031 m) 2 = 1 . 15182 × 10 − 5 Wb . The radius of the solenoid is not required since it is smaller that the plane circular surface. 002 (part 1 of 2) 10.0 points A magnetic field of 1 T is perpendicular to a square coil of 12 turns. The length of each side of the coil is 4 cm. Find the magnetic flux through coil. Correct answer: 19 . 2 mWb. Explanation: Let : B = 1 T , N = 12 , ℓ = 4 cm = 0 . 04 m , and θ = 0 ◦ . The magnetic flux is Φ = N B A cos θ = N B ℓ 2 cos θ = 12(1 T) (0 . 04 m) 2 cos 0 ◦ · 10 3 mWb 1 Wb = 19 . 2 mWb . 003 (part 2 of 2) 10.0 points Find the magnetic flux through the coil if the magnetic field makes an angle of 60 ◦ with the normal to the plane of the coil. Correct answer: 9 . 6 mWb. Explanation: Let : θ = 60 ◦ . The magnetic flux is Φ = N B A cos θ = N B ℓ 2 cos θ = 12(1 T) (0 . 04 m) 2 cos 60 ◦ · 10 3 mWb 1 Wb = 9 . 6 mWb . keywords: 004 10.0 points A wire in the shape of an equilateral trian gle 7 . 8 cm on a side is placed in a uniform magnetic field of magnitude 0 . 11 T. wilson (kw22588) – HW10 – Mackie – (20224) 2 If the field makes an angle of 53 . 7 ◦ with the plane of the triangle, determine the magnetic flux through the triangle....
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 Spring '08
 Turner
 Physics, Magnetic Field

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