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Question
A .0.5m long solenoid of 10 turns/cm has area of cross-section 1cm2 . Calculate the voltage induced across its ends if the current in the solenoid is changed from 1A to 2A in 0.1s.
Solution
l = 0. 5m
n = 10 turns /cm = 10 × 10+2 turns/ m
a = 1 cm2 = 10-4
`(di)/(dt) = (2-1)/0.1 = 1/(0.1) = 10 `A / s
`ε = -L (di)/(dt)`
` = mu_0 n^2 Al (di)/(dt)`
= 4π × 10-7 × (10+3)2 × 10-4 × 0.5 × 10
= 4π × 10-7 × 106 × 10-4 × 5 × 10-1 × 10
ε = 20π × 10-5 V
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