Question

The change of flux is greatest at $\theta$ is equal to (given, ${\varphi }_B=NBA\cos \omega t)$

• A. $90^{\circ },270^{\circ }$
• B. $90^{\circ },45^{\circ }$
• C. $60^{\circ },90$
• D. $180^{\circ },90^{\circ }$

Answer 1

Answer: (A)

$\frac{d{\varphi }_B}{dt}=-NBA\omega \sin \omega t$,
change of flux is greatest for
$\omega t=\theta =90^{\circ },270^{\circ },\theta =90^{\circ },270^{\circ }$.