Q. No.The charge of a parallel plate capacitor is varying as \(q = q_{0} \sin\omega t\). Find the magnitude of displacement current through the capacitor.
(Plate Area = \(A\), separation of plates = \(d\))
1. \(q_{0}\cos \left(\omega t \right)\)
2. \(q_{0} \omega \sin\omega t\)
3. \(q_{0} \omega \cos \omega t\)
4. \(\frac{q_{0} A \omega}{d} \cos \omega t\)
(Plate Area = \(A\), separation of plates = \(d\))
1. \(q_{0}\cos \left(\omega t \right)\)
2. \(q_{0} \omega \sin\omega t\)
3. \(q_{0} \omega \cos \omega t\)
4. \(\frac{q_{0} A \omega}{d} \cos \omega t\)
In electromagnetic wave the phase difference between electric and magnetic field vectors \(\vec E~\text{and}~\vec B\) is:
1. \(0\)
2. \(\frac{\pi}{2}\)
3. \(\pi\)
4. \(\frac{\pi}{4}\)
An electromagnetic wave going through the vacuum is described by
Which is the following is/are independent of the wavelength?
| 1. | \(k\) | 2. | \(k \over \omega\) |
| 3. | \(k \omega\) | 4. | \( \omega\) |
In a plane EM wave, the electric field oscillates sinusoidally at a frequency of \(2.5\times 10^{10}~\text{Hz}\) and amplitude \(480\) V/m. The amplitude of the oscillating magnetic field will be:
1. \(1.52\times10^{-8}~\text{Wb/m}^2\)
2. \(1.52\times10^{-7}~\text{Wb/m}^2\)
3. \(1.6\times10^{-6}~\text{Wb/m}^2\)
4. \(1.6\times10^{-7}~\text{Wb/m}^2\)
A lamp radiates power \(P_0\) uniformly in all directions. The amplitude of electric field strength \(E_0\) at a distance \(r\) from it is:
1. \(E_{0} = \frac{P_{0}}{2 \pi\varepsilon_{0} cr^{2}}\)
2. \(E_{0} = \sqrt{\frac{P_{0}}{2 \pi\varepsilon_{0} cr^{2}}}\)
3. \(E_{0} = \sqrt{\frac{P_{0}}{4 \pi\varepsilon_{0} cr^{2}}}\)
4. \(E_{0} = \sqrt{\frac{P_{0}}{8 \pi\varepsilon_{0} cr^{2}}}\)
The intensity of visible radiation at a distance of \(1\) m from a bulb of \(100\) W which converts only \(5\%\) of its power into light, is:
1. \(0.4\) W/m2
2. \(0.5\) W/m2
3. \(0.1\) W/m2
4. \(0.01\) W/m2
Which of the following statements about electromagnetic waves is/are correct:
| A. | X-rays in vacuum travel faster than light waves in vacuum. |
| B. | The energy of an X-ray photon is greater than that of a light photon. |
| C. | Light can be polarised but X-ray cannot. |
1. A and B
2. B and C
3. A, B and C
4. B only
(\(\rho\) = volume charge density, \(J\) = current density, \(m\) = pole strength, \(V\) = volume, \(S\) is a closed surface, and \(C\) is closed loop)
| 1. | \(\oint_S \vec{E} \cdot \overrightarrow{d S}=\frac{1}{\varepsilon_0} \int_V \rho d V\) |
| 2. | \(\oint_S \vec{B} \cdot \overrightarrow{d S}=\frac{m}{\mu_0}\) |
| 3. | \(\oint_S \vec{E} \cdot \overrightarrow{d l}=-\frac{d}{d t} \int_S \vec{B} \cdot \overrightarrow{d S}\) |
| 4. | \(\oint_S \vec{H} \cdot \overrightarrow{d S}=\int_C\left(\vec{J}+\frac{d}{d t}\left(\varepsilon_0 \vec{E}\right)\right) \cdot \overrightarrow{d S}\) |
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