Assertion (A): When a circular coil,placed in | vedclass

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(C) The magnetic flux $\phi_B$ linked with a coil is given by $\phi_B = \vec{B} \cdot \vec{A} = BA \cos 	heta$,where $	heta$ is the angle between th

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$A$ is true,$R$ is false.

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(C) The magnetic flux $\phi_B$ linked with a coil is given by $\phi_B = \vec{B} \cdot \vec{A} = BA \cos 	heta$,where $	heta$ is the angle between the magnetic field vector $\vec{B}$ and the area vector $\vec{A}$.When the plane of the coil is parallel to the magnetic field,the area vector $\vec{A}$ (which is perpendicular to the plane) is perpendicular to the magnetic field $\vec{B}$. Thus,$	heta = 90^\circ$ and $\phi_B = BA \cos 90^\circ = 0$.Since the magnetic field is uniform and the coil expands radially while remaining in the same plane parallel to the field,the flux remains zero at all times. Therefore,the induced emf $\varepsilon = -\frac{d\phi_B}{dt} = 0$.Thus,Assertion $(A)$ is true.The Reason $(R)$ states that there is a constant magnetic field in the perpendicular direction to the plane of the coil. If this were true,the flux would be $\phi_B = BA$,and expanding the coil would change the area $A$,thereby inducing an emf. Since the problem states the plane is parallel to the field,the Reason $(R)$ is false.

Assertion $(A)$: When a circular coil,placed in a region with its plane parallel to a magnetic field,expands radially outwards,no emf is induced in it.
Reason $(R)$: There is a constant magnetic field in the perpendicular (to the plane of the coil) direction.

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Assertion $(A)$: When a circular coil,placed in a region with its plane parallel to a magnetic field,expands radially outwards,no emf is induced in it.Reason $(R)$: There is a constant magnetic field in the perpendicular (to the plane of the coil) direction.