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ELECTROMAGNETIC INDUCTION — Physics STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 SciencePhysicsELECTROMAGNETIC INDUCTION2 Marks
Question
Give expression for induced emf in AC generator. Discuss, with fogure, how this emf changes with time during one rotation of coil.
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Answer

→Expression for induced emf in AC generator is
$\varepsilon=\varepsilon_0 \sin \omega t$
where $\varepsilon_0= NBA \omega$
→Induced emf changes periodically with time during one complete rotation. This is shown step-wise in following figure of graph of emf $\varepsilon \rightarrow$ time $t$. Time $t$ is in the form of periodic time T.
→It is clear that when $\theta=\frac{\pi}{2}$ or $\frac{3 \pi}{2}$, induced emf is maximum.
→When $\theta=0$ or $\pi, 2 \pi$ induced emf is zero.
→This situation is repeated till rotation of coil continues and induced emf $\varepsilon$ is produced between $+\varepsilon_0$ and $-\varepsilon_0$.

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