Q. No.The energy associated with an electric field is \((U_E)\) and with a magnetic field is \((U_B)\) for an electromagnetic wave in free space. Then:
1. \(U_E= \dfrac{U_B }{2}\)
2. \(U_E>U_B\)
3. \(U_E<U_B\)
4. \(U_E=U_B\)
1. \(U_E= \dfrac{U_B }{2}\)
2. \(U_E>U_B\)
3. \(U_E<U_B\)
4. \(U_E=U_B\)
Subtopic: Properties of EM Waves |
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If \(\vec{E}\) and \(\vec{B}\) represent the electric field vector and magnetic field vector, respectively, in an electromagnetic wave then the direction of EM wave is along:
| 1. | \(\vec{E}\) | 2. | \(\vec{B}\) |
| 3. | \(\vec{E}\times\vec{B}\) | 4. | \(\vec{B}\times\vec{E}\) |
Subtopic: Properties of EM Waves |
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NEET - 2024
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An electromagnetic wave has an electric field given by \( \vec{E}=(9.6 \hat{j}) \sin \left[2 \pi\left\{30 \times 10^6 t-\frac{1}{10} x\right\}\right], x\) and \(t\) are in S.l units. The maximum magnetic field (\(B_0\)) associated with this wave is:
1. \( 3.2\times10^{-8}~\text T\)
2. \( 9.6\times10^{-8}~\text T\)
3. \( 1.7\times10^{-8}~\text T\)
4. \( 10^{-7}~\text T\)
1. \( 3.2\times10^{-8}~\text T\)
2. \( 9.6\times10^{-8}~\text T\)
3. \( 1.7\times10^{-8}~\text T\)
4. \( 10^{-7}~\text T\)
Subtopic: Properties of EM Waves |
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Average energy density of an EM wave with electric field amplitude E0 and magnetic field amplitude B0 is equal to
\(\begin{align} & {{1}{.}\;\frac{1}{2}{\varepsilon}_{0}{E}_{0}^{2}}\\ & {{2}{.}\;\frac{{B}_{0}^{2}}{{\mathit{\mu}}_{0}}}\\ & {{3}{.}\;{\varepsilon}_{0}{E}_{0}^{2}}\\ & {{4}{.}\;\frac{1}{2}{\mathit{\mu}}_{0}{E}_{0}^{2}} \end{align} \)
\(\begin{align} & {{1}{.}\;\frac{1}{2}{\varepsilon}_{0}{E}_{0}^{2}}\\ & {{2}{.}\;\frac{{B}_{0}^{2}}{{\mathit{\mu}}_{0}}}\\ & {{3}{.}\;{\varepsilon}_{0}{E}_{0}^{2}}\\ & {{4}{.}\;\frac{1}{2}{\mathit{\mu}}_{0}{E}_{0}^{2}} \end{align} \)
Subtopic: Properties of EM Waves |
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A plane electromagnetic wave travels in a vacuum along the \({z\text{-}}\)direction. Then the directions of its electric and magnetic field vectors will be:
| 1. | in the \({x\text{-}y}\) plane and they are parallel to each other. |
| 2. | in the \({x\text{-}y}\) plane and they are mutually perpendicular to each other. |
| 3. | in the \({y\text{-}z}\) plane and they are mutually perpendicular to each other. |
| 4. | in the \({z\text{-}x}\) plane and they are parallel to each other. |
Subtopic: Properties of EM Waves |
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The electric and the magnetic fields, associated with an electromagnetic wave, propagating along the positive Z-axis, can be represented by:
1. \(\left [E=E_{0}\hat{k},~B=B_{0}\hat{i} \right ]\)
2. \(\left [E=E_{0}\hat{j},~B=B_{0}\hat{j} \right ]\)
3. \(\left [E=E_{0}\hat{j},~B=B_{0}\hat{k} \right ]\)
4. \(\left [E=E_{0}\hat{i},~B=B_{0}\hat{j} \right ]\)
Subtopic: Properties of EM Waves |
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AIPMT - 2011
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In an electromagnetic wave, the electric field is given as \(\vec{E}=E_0 \sin (\omega t-k z) \hat{i} ,\) then the corresponding magnetic field will be:
| 1. | \(E_0 c \sin (\omega t-k z) \hat{j}\) | 2. | \(\dfrac{E_0}{c} \sin (\omega t-k z) \hat{j} \) |
| 3. | \(\dfrac{E_0}{c} \cos (\omega t-k z) \hat{i}\) | 4. | \(\dfrac{E_0}{c} \sin (\omega t-k z) \hat{i}\) |
Subtopic: Properties of EM Waves |
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An EM wave propagating in \(x\text-\)direction has a wavelength of \(8~\text{mm}\). The electric field vibrating \(y\text-\)direction has maximum magnitude of \(60~\text{Vm}^{-1}\). Choose the correct equations for electric and magnetic fields if the EM wave is propagating in a vacuum:
| 1. | \(E_y=60 \sin \left[\frac{\pi}{4} \times 10^3\left(x-3 \times 10^8 t\right)\right] \hat{j}~ \text{Vm}^{-1}\\ {B}_{z}=2 \sin \left[\frac{\pi}{4} \times 10^3\left({x}-3 \times 10^8 {t}\right)\right] \hat{k}~\text{T} \) |
| 2. | \({E}_{y}=60 \sin \left[\frac{\pi}{4} \times 10^3\left({x}-3 \times 10^8 {t}\right)\right] \hat{j}~\text{Vm}^{-1}\\ {B}_{z}=2 \times 10^{-7} \sin \left[\frac{\pi}{4} \times 10^3\left({x}-3 \times 10^8 {t}\right)\right]\hat{k}~ \text{T}\) |
| 3. | \(E_y=2 \times 10^{-7} \sin \left[\frac{\pi}{4} \times 10^3\left({x}-3 \times 10^8 {t}\right)\right] \hat{j}~{\text{Vm}}^{-1}\\ B_z= 60 \sin \left[\frac{\pi}{4} \times 10^3\left(x-3 \times 10^8 t\right)\right] \hat{k} ~\text{T} \) |
| 4. | \(E_y=2 \times 10^{-7} \sin \left[\frac{\pi}{4} \times 10^4\left(x-4 \times 10^8 t\right)\right] \hat{j}~\text{Vm}^{-1}\\ {B}_{z}=60 \sin \left[\frac{\pi}{4} \times 10^4\left({x}-4 \times 10^8 {t}\right)\right] \hat{k}~\text{T} \) |
Subtopic: Properties of EM Waves |
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The electromagnetic waves travel in a medium at a speed of \(2.0\times 10^{8}~\text{m/s}\). The relative permeability of the medium is \(1.0\). The relative permittivity of the medium will be:
1. \(2.25\)
2. \(4.25\)
3. \(6.25\)
4. \(8.25\)
1. \(2.25\)
2. \(4.25\)
3. \(6.25\)
4. \(8.25\)
Subtopic: Properties of EM Waves |
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During the propagation of the electromagnetic wave in a medium:
| 1. | electric energy density is double the magnetic energy density. |
| 2. | electric energy density is half the magnetic energy density. |
| 3. | electric energy density is equal to magnetic energy density. |
| 4. | the electric energy density & magnetic energy density are not related to each other. |
Subtopic: Properties of EM Waves |
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