91影视

There is a magnetic field. Magnetic fields are vector fields that describe the magnetic influence of currents and magnetised materials. Magnetic fields are frequently seen in everyday life in the form of permanent magnets, which attract or repel other magnets by pulling on magnetic materials (such as iron).

(a) Magnetic flux is the amount of magnetic field that flows through a loop in area A. Is when magnet is parallel to the normal of a plane, the magnetic flux is given

${\mathrm{桅}}_m=BA$

The triangle's area is equal to half of its base multiplied by its height. The height is derived from

$h=\left(20\mathrm{cm}\right)\sin 鈦�60=17.3\mathrm{cm}$

So, we get the area of the triangle by

$A=\frac{1}{2}bh=\frac{1}{2}\left(0.20\mathrm{m}\right)\left(17.3脳{10}^{鈭�2}\mathrm{m}\right)=1.73脳{10}^{鈭�2}{\mathrm{m}}^2$

Because the magnetic field flows through half of the total loop, the flux area is

$A_{\mathrm{桅}}=\frac{1}{2}\left(1.73脳{10}^{鈭�2}{\mathrm{m}}^2\right)=8.65脳{10}^{鈭�3}{\mathrm{m}}^2$

Now, we plug the values forlocalid="1648879727201" $A_{桅},胃=0$and B into equation (2) to get ${桅}_m$

${\mathrm{桅}}_m=B{A}_{\mathrm{桅}}\cos 鈦�胃=\left(0.10\mathrm{T}\right)\left(8.65脳{10}^{鈭�3}{\mathrm{m}}^2\right)\cos 鈦�0^{鈭�}$

(b) According to Lenz's law, the direction of the induced emf drives current around a wire loop in the opposite direction of the change in magnetic flux that causes the emf. When the applied magnetic field's strength is reduced, the induced magnetic field points in the same direction as the applied magnetic field B. As a result, the induced magnetic field is pointing into the page.

To determine the direction of the induced current, apply the right-hand rule. Your four wrapped fingers represent the direction of the induced magnetic field (into the page), and your thumb represents the direction of the current.

$\text{(a)}{\mathrm{桅}}_m=8.6脳{10}^{鈭�4}\mathrm{Wb}\text{.}$

(b) The induced current flows clockwise.