JEE Main 2017 (Online) 8th April Morning Slot | Alternating Current and Electromagnetic Induction Question 186 | Physics

JEE Main 2017 (Online) 8th April Morning Slot

MCQ (Single Correct Answer)

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A small circular loop of wire of radius a is located at the centre of a much larger circular wire loop of radius b. The two loops are in the same plane. The outer loop of radius b carries an alternating current I = I_o cos ($$\omega $$t). The emf induced in the smaller inner loop is nearly :

$${{\pi {\mu _o}{I_o}} \over 2}.{{{a^2}} \over b}\,\omega \sin \left( {\omega t} \right)$$

$${{\pi {\mu _o}{I_o}} \over 2}.{{{a^2}} \over b}\,\omega \cos \left( {\omega t} \right)$$

$$\pi {\mu _o}{I_o}\,{{{a^2}} \over b}\omega \sin \left( {\omega t} \right)$$

$${{\pi {\mu _o}{I_o}\,{b^2}} \over a}\omega \cos \left( {\omega t} \right)$$

JEE Main 2017 (Offline)

MCQ (Single Correct Answer)

-1

In a coil of resistance 100 $$\Omega $$, a current is induced by changing the magnetic flux through it as shown in the figure. The magnitude of change in flux through the coil is:

JEE Main 2017 (Offline) Physics - Alternating Current and Electromagnetic Induction Question 190 English

JEE Main 2017 (Offline) Physics - Alternating Current and Electromagnetic Induction Question 190 English

275 Wb

200 Wb

225 Wb

250 Wb

JEE Main 2016 (Online) 10th April Morning Slot

MCQ (Single Correct Answer)

-1

A conducting metal circular-wire-loop of radius r is placed perpendicular to a magnetic field which varies with time as
B = B₀e$${^{{{ - t} \over r}}}$$ , where B₀ and $$\tau $$ are constants, at time t = 0. If the resistance of the loop is R then the heat generated in the loop after a long time (t $$ \to $$ $$\infty $$) is :

$${{{\pi ^2}{r^4}B_0^4} \over {2\tau R}}$$

$${{{\pi ^2}{r^4}B_0^2} \over {2\tau R}}$$

$${{{\pi ^2}{r^4}B_0^2R} \over \tau }$$

$${{{\pi ^2}{r^4}B_0^2} \over {\tau R}}$$

JEE Main 2016 (Online) 10th April Morning Slot

MCQ (Single Correct Answer)

-1

Consider an electromagnetic wave propagating in vacuum. Choose the correct statement :

For an electromagnetic wave propagating in +x direction the electric field is $$\vec E = {1 \over {\sqrt 2 }}{E_{yz}}{\mkern 1mu} \left( {x,t} \right)\left( {\hat y - \hat z} \right)$$

and the magnetic field is $$\vec B = {1 \over {\sqrt 2 }}{B_{yz}}{\mkern 1mu} \left( {x,t} \right)\left( {\hat y + \hat z} \right)$$

For an electromagnetic wave propagating in +x direction the electric field is $$\vec E = {1 \over {\sqrt 2 }}{E_{yz{\mkern 1mu} }}\left( {y,z,t} \right)\left( {\hat y + \hat z} \right)$$

and the magnetic field is $$\vec B = {1 \over {\sqrt 2 }}{B_{yz{\mkern 1mu} }}\left( {y,z,t} \right)\left( {\hat y + \hat z} \right)$$

For an electromagnetic wave propagating in + y direction the electric field is $$\overrightarrow E = {1 \over {\sqrt 2 }}{E_{yz{\mkern 1mu} }}\left( {x,t} \right)\widehat y$$
and the magnetic field is $$\vec B = {1 \over {\sqrt 2 }}{B_{yz{\mkern 1mu} }}\left( {x,t} \right)\widehat z$$

For an electromagnetic wave propagating in + y direction the electric field is $$\overrightarrow E = {1 \over {\sqrt 2 }}{E_{yz{\mkern 1mu} }}\left( {x,t} \right)\widehat z$$
and the magnetic field is $$\overrightarrow B = {1 \over {\sqrt 2 }}{B_{z{\mkern 1mu} }}\left( {x,t} \right)\widehat y$$

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