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## Question Text#

A long solenoid with $$n$$ = turns per centimeter has a cross-sectional area of $$\rm\ cm^2$$ and carries a current of $$\textrm{A}$$. A coil with turns encircles the solenoid. When the current through the solenoid is turned off, it decreases to zero in $$\textrm{ s}$$. What is the average emf induced in the coil?

$$\varepsilon=$$ $$\rm\ V$$