Question

Find flux through a circular disc of radius R kept in a region of magnetic field perpendicular to the disc.The magnitude of field at a distance r from centre of the disc is given by B= ar where a is a constant.​

Answer 1

Given:

The magnitude of field at a distance r from centre of the disc is given by B= ar. Circular disc of radius R.

To find:

Magnetic Flux?

Calculation:

Let Magnetic Flux be $\phi$.

$\therefore \phi = B \times A \times \cos( \theta)$

• $\theta$ is the angle between area vector and magnetic field vector.

$\implies \phi = B \times A \times \cos( {0}^{ \circ} )$

$\implies \phi = B \times A$

$\implies \phi = B \times (\pi {R}^{2} )$

$\implies \phi = ar\times (\pi {R}^{2} )$

$\implies \phi = \pi ar {R}^{2}$

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