The property which is not of an electromagnetic wave travelling in free space is that:

1. | the energy density in electric field is equal to energy density in magnetic field. |

2. | they travel with a speed equal to \(\dfrac{1}{\sqrt{\mu_0~ \varepsilon_0}} .\) |

3. | they originate from charges moving with uniform speed. |

4. | they are transverse in nature. |

Subtopic: Properties of EM Waves |

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From NCERT

NEET - 2024

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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. \(\vec{B}\times\vec{E}\)

1. \(\vec{E}\)

2. \(\vec{B}\)

3. \(\vec{E}\times\vec{B}\)

4. \(\vec{B}\times\vec{E}\)

Subtopic: Properties of EM Waves |

84%

From NCERT

NEET - 2024

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If the ratio of relative permeability and relative permittivity of a uniform medium is \(1 : 4.\) The ratio of the magnitudes of electric field intensity \((E)\) to the magnetic field intensity \((H)\) of an EM wave propagating in that medium is:

\(\left(\text{Given that}\sqrt{\frac{\mu_0}{\varepsilon_0}}=120\pi\right)\)

1. \(30\pi:1\)

2. \(1:120\pi\)

3. \(60\pi:1\)

4. \(120\pi:1\)

\(\left(\text{Given that}\sqrt{\frac{\mu_0}{\varepsilon_0}}=120\pi\right)\)

1. \(30\pi:1\)

2. \(1:120\pi\)

3. \(60\pi:1\)

4. \(120\pi:1\)

Subtopic: Properties of EM Waves |

From NCERT

NEET - 2024

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In a plane electromagnetic wave travelling in free space, the electric field component oscillates sinusoidally at a frequency of \(2.0\times 10^{10}~ \text{Hz}\) and amplitude \(48~\text{Vm}^{-1}\). Then the amplitude of the oscillating magnetic field is: (Speed of light in free space \(3\times 10^{8}~ \text{ms}^{-1}\))

1. \(1.6 \times 10^{-6} ~\text{T}\)

2. \(1.6 \times 10^{-9} ~\text{T}\)

3. \(1.6 \times 10^{-8} ~\text{T}\)

4. \(1.6 \times 10^{-7} ~\text{T}\)

1. \(1.6 \times 10^{-6} ~\text{T}\)

2. \(1.6 \times 10^{-9} ~\text{T}\)

3. \(1.6 \times 10^{-8} ~\text{T}\)

4. \(1.6 \times 10^{-7} ~\text{T}\)

Subtopic: Properties of EM Waves |

58%

From NCERT

NEET - 2023

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\(\varepsilon_0\) and \(\mu_0\) are the electric permittivity and magnetic permeability of free space respectively. If the corresponding quantities of a medium are \(2\varepsilon_0\) and \(1.5\mu_0\) respectively, the refractive index of the medium will nearly be:

1. \(\sqrt2\)

2. \(\sqrt3\)

3. \(3\)

4. \(2\)

1. \(\sqrt2\)

2. \(\sqrt3\)

3. \(3\)

4. \(2\)

Subtopic: Properties of EM Waves |

78%

From NCERT

NEET - 2023

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When light propagates through a material medium of relative permittivity, \(\varepsilon_{r}\) and relative permeability, \(\mu_{r}\) the velocity of light, \(v\) is given by:

(\(c\) = velocity of light in vacuum)

1. \(v=\dfrac{{c}}{\sqrt{\varepsilon_{r} \mu_{{r}}}}\)

2. \(v={c}\)

3. \(v=\sqrt{\dfrac{\mu_{{r}}}{\varepsilon_{{r}}}}\)

4. \(v=\sqrt{\dfrac{\varepsilon_{{r}}}{\mu_{{r}}}}\)

(\(c\) = velocity of light in vacuum)

1. \(v=\dfrac{{c}}{\sqrt{\varepsilon_{r} \mu_{{r}}}}\)

2. \(v={c}\)

3. \(v=\sqrt{\dfrac{\mu_{{r}}}{\varepsilon_{{r}}}}\)

4. \(v=\sqrt{\dfrac{\varepsilon_{{r}}}{\mu_{{r}}}}\)

Subtopic: Properties of EM Waves |

85%

From NCERT

NEET - 2022

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An electromagnetic wave is moving along negative \(z (-z)\) direction and at any instant of time, at a point, its electric field vector is \(3\hat j~\text{V/m}\). The corresponding magnetic field at that point and instant will be: (Take \(c=3\times10^{8}~\text{ms}^{-1}\))

1. | \(10\hat i~\text{nT}\) | 2. | \(-10\hat i~\text{nT}\) |

3. | \(\hat i~\text{nT}\) | 4. | \(-\hat i~\text{nT}\) |

Subtopic: Properties of EM Waves |

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From NCERT

NEET - 2022

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The magnetic field of a plane electromagnetic wave

is given by,

\(\vec B=3\times10^{-8}\text{cos}(1.6\times10^3x+48\times10^{10}t)\hat j~\text{T}.\)

The associated electric field will be:

is given by,

\(\vec B=3\times10^{-8}\text{cos}(1.6\times10^3x+48\times10^{10}t)\hat j~\text{T}.\)

The associated electric field will be:

1. | \(3 \times 10^{-8} \text{cos}\left(1.6 \times 10^3 x+48 \times 10^{10} t\right) \hat{i}~\text{ V/m}\) |

2. | \(3 \times 10^{-8} \text{sin} \left(1.6 \times 10^3 {x}+48 \times 10^{10} {t}\right) \hat{{i}}~ \text{V} / \text{m}\) |

3. | \(9 \text{sin} \left(1.6 \times 10^3 {x}-48 \times 10^{10} {t}\right) \hat{{k}} ~~\text{V} / \text{m}\) |

4. | \(9 \text{cos} \left(1.6 \times 10^3 {x}+48 \times 10^{10} {t}\right) \hat{{k}}~~\text{V} / \text{m}\) |

Subtopic: Properties of EM Waves |

56%

From NCERT

NEET - 2022

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The ratio of the magnitude of the magnetic field and electric field intensity of a plane electromagnetic wave in free space of permeability \(\mu_0\) and permittivity \(\varepsilon_0\) is:

(Given that \(c=\) velocity of light in free space)

1. \(c\)

2. \(\dfrac1c\)

3. \(\dfrac{c}{\sqrt{\mu_0\varepsilon_0}}\)

4. \(\dfrac{\sqrt{\mu_0\varepsilon_0}}{c}\)

(Given that \(c=\) velocity of light in free space)

1. \(c\)

2. \(\dfrac1c\)

3. \(\dfrac{c}{\sqrt{\mu_0\varepsilon_0}}\)

4. \(\dfrac{\sqrt{\mu_0\varepsilon_0}}{c}\)

Subtopic: Properties of EM Waves |

58%

From NCERT

NEET - 2022

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For a plane electromagnetic wave propagating in the \(x\)-direction, which one of the following combinations gives the correct possible directions for the electric field \((E)\) and magnetic field \((B)\) respectively?

1. \(\hat{j}+\hat{k},~-\hat{j}-\hat{k}\)

2. \(-\hat{j}+\hat{k},~-\hat{j}+\hat{k}\)

3. \(\hat{j}+\hat{k},~\hat{j}+\hat{k}\)

4. \(-\hat{j}+\hat{k},~-\hat{j}-\hat{k}\)

1. \(\hat{j}+\hat{k},~-\hat{j}-\hat{k}\)

2. \(-\hat{j}+\hat{k},~-\hat{j}+\hat{k}\)

3. \(\hat{j}+\hat{k},~\hat{j}+\hat{k}\)

4. \(-\hat{j}+\hat{k},~-\hat{j}-\hat{k}\)

Subtopic: Properties of EM Waves |

From NCERT

NEET - 2021

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