Assertion : If the current in a solenoid is r | vedclass

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(C) The magnetic field $B$ produced by a solenoid is given by $B = \mu_0 n I$. When the current $I$ is reversed,the direction of the magnetic field $B

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If Assertion is correct but Reason is incorrect.

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(C) The magnetic field $B$ produced by a solenoid is given by $B = \mu_0 n I$. When the current $I$ is reversed,the direction of the magnetic field $B$ is reversed,but its magnitude remains the same.The magnetic field energy density $u$ is given by the formula $u = \frac{B^2}{2\mu_0}$.Since the energy density depends on the square of the magnetic field magnitude $(B^2)$,the sign of $B$ does not affect the energy density.Therefore,the total magnetic field energy stored in the solenoid,$U = u 	imes V$ (where $V$ is the volume),remains unchanged.However,the Reason states that the energy density is proportional to the magnetic field,which is incorrect because it is proportional to the square of the magnetic field $(B^2)$.Thus,the Assertion is correct,but the Reason is incorrect.

Assertion : If the current in a solenoid is reversed in direction while keeping the same magnitude,the magnetic field energy stored in the solenoid remains unchanged.
Reason : Magnetic field energy density is proportional to the magnetic field.

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Assertion : If the current in a solenoid is reversed in direction while keeping the same magnitude,the magnetic field energy stored in the solenoid remains unchanged.Reason : Magnetic field energy density is proportional to the magnetic field.