Get Answers to all your Questions

header-bg qa

A circular coil of radius 10 cm is placed in a uniform magnetic field of 3.0 \times 10^{-5}T with its plane perpendicular to the field initially. It is rotated at constant angular speed about an axis along the diameter of coil and perpendicular to magnetic field so that it undergoes half of rotation in 0.2s. The maximum value of EMF induced \left ( in\; \mu V \right )in the coil will be close to the integer_________
Option: 1 15
Option: 2 10
Option: 3 3
Option: 4 63

Answers (1)



\\\begin{array}{l} r=0.1 \mathrm{~m} \\ and \ \quad \frac{\mathrm{T}}{2}=0.2 \mathrm{sec} \Rightarrow \quad \mathrm{~T}=0.4 \ \mathrm{sec} \\ \mathrm{B}=3 \times 10^{-5} \mathrm{T} \end{array}

\begin{aligned} &\text { At any time }\\ &\text { flux } =\phi=B A \cos \omega t\\ &|\mathrm{emf}|=\left|\frac{\mathrm{d} \phi}{\mathrm{dt}}\right|=|\mathrm{BA} \omega \sin \omega \mathrm{t}|\\ &(\mathrm{emf})_{\max }=\mathrm{BA} \omega=\mathrm{BA} \frac{2 \pi}{\mathrm{T}}\\ &=\frac{3 \times 10^{-5} \times \pi \times(0.1)^{2} \times 2 \pi}{0.4}\\ &=\frac{6 \pi^{2}}{4} \times 10^{-6} &\left(\begin{array}{c} Use \ \pi^{2} \simeq 10 \end{array}\right)\\ &=15 \times 10^{-6}\\ &=15 \mu \mathrm{V} \end{aligned}

Posted by


View full answer

JEE Main high-scoring chapters and topics

Study 40% syllabus and score up to 100% marks in JEE