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Assume a bulb of efficiency \(2.5\%\) as a point source. The peak values of the electric field and magnetic field produced by the radiation coming from a \(100~\text{W}\) bulb at a distance of \(3~\text{m}\) are respectively:
| 1. | \( 2.5 ~\text{V/m}, ~2.2 \times 10^{-8} ~\text{T} \) |
| 2. | \( 3.6 ~\text{V/m}, ~ 3.6 ~\text{T} \) |
| 3. | \( 4.07~\text{V/m},~ 1.4 \times 10^{-8} ~\text{T}\) |
| 4. | \( 4.2 ~\text{V/m}, ~3.4 \times 10^{-6}~\text{T}\) |
Subtopic: Â Properties of EM Waves |
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Level 3: 35%-60%
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The magnetic field in a plane electromagnetic wave is given by \({B}=\left(2 \times 10^{-7}\right)\sin \left(0.5 \times 10^3 {x}+1.5 \times 10^{11} {t}\right )~\text{T}\). The wavelength and frequency of the wave are respectively:
| 1. | \( 2.16~\text{cm}, 24.1~\text{GHz} \) | 2. | \( 0.29~\text{cm}, 13.7~\text{GHz} \) |
| 3. | \( 3.23 ~\text{cm}, 20.0~\text{GHz} \) | 4. | \( 1.26~\text{cm}, 23.9~\text{GHz}\) |
Subtopic: Â Properties of EM Waves |
 75%
Level 2: 60%+
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The electric field of an electromagnetic wave is given by \(\overrightarrow E = E_0 \hat j \cos (\omega t - kx)+ E_0\hat i \sin (\omega t -kx) \).
The maximum value of the electric field in the wave is:
The maximum value of the electric field in the wave is:
| 1. | \(\dfrac {E_0} {\sqrt 2}\) | 2. | \(E_0\) |
| 3. | \(\sqrt 2 E_0\) | 4. | \(\sqrt 3 E_0\) |
Subtopic: Â Properties of EM Waves |
Level 3: 35%-60%
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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. | \(v=\sqrt{\dfrac{\varepsilon_{{r}}}{\mu_{{r}}}}\) |
Subtopic: Â Properties of EM Waves |
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Level 1: 80%+
NEET - 2022
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When an electromagnetic wave of frequency \(f_0\) undergoes refraction at the interface of two transparent (non-absorbing) media, the frequency of the transmitted wave is \(f_t.\) Then:
| 1. | \(f_t=f_0\) |
| 2. | \(f_t>f_0\) |
| 3. | \(f_t<f_0\) |
| 4. | \(f_t\neq f_0\) |
Subtopic: Â Properties of EM Waves |
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Level 2: 60%+
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A plane electromagnetic waveform given by: \(\vec {E}_1=E_0\hat j\sin(\omega t-kx)\)
propagates along the \(x\)-axis. A second waveform given by: \(\vec {E}_2=E_0\hat k\sin(\omega t-kx)\)
is also allowed to propagate. The magnetic field has the amplitude: (Assume speed of light in vacuum is \(c\))
propagates along the \(x\)-axis. A second waveform given by: \(\vec {E}_2=E_0\hat k\sin(\omega t-kx)\)
is also allowed to propagate. The magnetic field has the amplitude: (Assume speed of light in vacuum is \(c\))
| 1. | \(\dfrac{E_0}{c}\) | 2. | \(\dfrac{E_0}{2c}\) |
| 3. | \(\dfrac{\sqrt2E_0}{c}\) | 4. | Zero |
Subtopic: Â Properties of EM Waves |
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Level 2: 60%+
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A plane electromagnetic wave is given by its electric field: \(\vec {E}=\vec {E_0}\cos\dfrac{\omega}{c}(ct-\beta x)\)
where \(\omega\) and \(\beta\) are constants, \(t\) is the time and \(x\) represents the \(x\text-\)coordinate. \(c\) is the speed of the light in vacuum.
The value of \(\beta,\)
where \(\omega\) and \(\beta\) are constants, \(t\) is the time and \(x\) represents the \(x\text-\)coordinate. \(c\) is the speed of the light in vacuum.
The value of \(\beta,\)
| 1. | cannot be less than \(1\). |
| 2. | equals \(1\), always. |
| 3. | cannot be greater than \(1\). |
| 4. | can be any non-zero value. |
Subtopic: Â Properties of EM Waves |
Level 3: 35%-60%
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An electromagnetic waveform given by \(\vec{E}=E_{0} \hat{j} \sin \omega t\cos k x\) is set up in a certain region of space, where \(\vec{E}\) represents the electric field. The magnetic field associated with this waveform oscillates along the direction of:
1. \(\hat {i}\)
2. \(\hat {j}\)
3. \(\hat{k} \)
4. \(\hat{j} + \hat{k}\)
1. \(\hat {i}\)
2. \(\hat {j}\)
3. \(\hat{k} \)
4. \(\hat{j} + \hat{k}\)
Subtopic: Â Properties of EM Waves |
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Level 2: 60%+
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The maximum electric field of a plane electromagnetic wave traveling through a vacuum is \(300~\text{V/m}.\) The maximum magnetic field of this wave is:
1. \(300~\text{T}\)
2. \(10^{-6}~\text{T}\)
3. \(9 \times 10^{10}~\text{T}\)
4. \(300\sqrt {2}~\text{T}\)
1. \(300~\text{T}\)
2. \(10^{-6}~\text{T}\)
3. \(9 \times 10^{10}~\text{T}\)
4. \(300\sqrt {2}~\text{T}\)
Subtopic: Â Properties of EM Waves |
 88%
Level 1: 80%+
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The average electric field associated with the plane electromagnetic wave \(\vec E = E_0 \hat {i} \sin (wt - kz)\) is:
| 1. | \(E_0 \hat i\) | 2. | \(\dfrac {E_0} { \sqrt 2}\) \(\hat i \) |
| 3. | \(\sqrt 2E_0 \hat i\) | 4. | zero |
Subtopic: Â Properties of EM Waves |
 55%
Level 3: 35%-60%
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