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| Grade Summary Submissions 12 Begin Date: 10/7/2017 8:15:00 PM -- Due Date: 11/

ID: 1792761 • Letter: #

Question

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Grade Summary

Submissions

12 Begin Date: 10/7/2017 8:15:00 PM -- Due Date: 11/2/2017 7:00:00 PM End Date: 11/2/2017 7:00:00 PM (25%) Problem 3: Suppose a 52.5 cm long, 11.5 cm diameter solenoid has 1000 loops. 33% Part (a) Calculate the self-inductance of it in mH. L =

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Grade Summary

Deductions 0% Potential 100%

Submissions

Attempts remaining: 20 (0% per attempt) detailed view . 33% Part (b) How much energy is stored in this inductor when 17.5 A of current flows through it? Give your answer in J.
33% Part (c) How fast can it be turned off (in s) if the average induced emf cannot exceed 2.95 V?

Explanation / Answer

a) A = pi d2 / 4 = pi * 0.1152 / 4 = 0.0104 m2

L = mu0 N2 A / l = (4 pi * 10-7 * 10002 * 0.0104) / (0.525)

= 24.89 mH

b) Energy stored = 1/2 L i2

= 1/2 * 24.89 * 10-3 * 17.52

energy stored = 3.81 J

c) dt = - L * di / 2.95 = -24.89 * 10-3 * (0 - 17.5) / 2.95

= 0.148 s