A long solenoid with 10 turns per cm has a small loop of area `3cm^(2)` placed inside, normal to the axis of the solenoid. If the currnet carried by t
A long solenoid with 10 turns per cm has a small loop of area `3cm^(2)` placed inside, normal to the axis of the solenoid. If the currnet carried by the solenoid changes steadily from 2 A to 4 A in 0.2 s, what is the induced voltage in the loop, while the current is changing?
A. `4.2xx10^(-8)V`
B. `2.8xx10^(-8)V`
C. `7.3xx10^(-6)V`
D. `7.3xx10^(-6)V`
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Correct Answer - D
Here, `(N)/(l)=10` turns per cm = 1000 turns per m
`A=3cm^(2)=3xx10^(-4)m^(2)or(dl)/(dt)=(4-2)/(0.2)=10As^(-1)`
Also `epsi=(dphi)/(dt)=(d)/(dt)(BA)=A(d)/(dt)(mu_(0)(N)/(l))(dl)/(dt)`
`=3xx10^(-4)xx4pixx10^(-7)xx1000xx10=3.8xx10^(-6)V`
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