Suppose this page is perpendicular to a uniform magnetic field and the magnetic flux through it is 5 wb. (The “weber” is the unit for magnetic flux, given by volts×seconds.) If the page is turned by 30 degrees around an edge the flux through it will be:

The correct option is B

4.3 wb

Step 1: Given data

Magnetic flux$\left(\phi \right)$=5 Wb

Step 2: Calculation of the flux

The formula to calculate the flux is:

$\phi =BA\cos \theta$

By substituting the values, we get

5= BA

Here area vector and the magnetic field are in the same direction so the angle is zero.

So,

$\cos 0°=1$

Now $\cos \theta =30°$

$Cos30°=0.866$

Therefore,

$$\begin{gathered} \phi =BA\cos 30° \\ \phi =5(0.866) \\ \phi =4.3wb \end{gathered}$$

Step 3: Final answer

Hence, If the page is turned by 30 degrees around an edge the flux through it will be:4.3 Wb