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A solenoid containing 207 turns if the length of the solenoid is 37.3 cm and its cross-sectional area is 6.77×10⁻⁴ m². Find the self-induced emf (positive value and unit in mV ) in the solenoid if the current in the solenoid decreases at the rate of 66.0 A/s.

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Final answer:

The self-induced emf in a solenoid can be calculated using Faraday's law and the formula for the self-inductance of a solenoid. By plugging in the given values, including the rate of change of current, the permeability of free space, the number of turns, the cross-sectional area, and the length of the solenoid, we can solve for the emf in mV.

Step-by-step explanation:

To solve the mathematical problem completely, we will calculate the self-induced emf in the solenoid by applying Faraday's law of electromagnetic induction. The self-induced emf (E) in a solenoid can be determined using the formula:

E = -L (dI/dt), where

L is the self-inductance of the solenoid,

dI/dt is the rate of change of current.

The self-inductance (L) can be calculated using the formula for a solenoid:

L = (μ0 * N^2 * A) / l, where

μ0 is the permeability of free space (μ0 = 4π x 10^-7 T·m/A),

N is the number of turns,

A is the cross-sectional area,

l is the length of the solenoid.

Plugging in the given values:

N = 207 turns,

A = 6.77×10−4 m2,

l = 37.3 cm = 0.373 m,

dI/dt = -66.0 A/s (the negative sign indicates a decrease in current).

Calculating L:

L = (4π x 10^-7 T·m/A * 2072 * 6.77×10−4 m2) / 0.373 m

Now, calculating the self-induced emf (E):

E = - L * (-66.0 A/s) = L * 66.0 A/s

After computation, the self-induced emf in millivolts (mV) will be obtained. Note: we only report the magnitude (positive value) as requested.

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