If an electromagnetic wave propagating through vacuum is described by \(E_y= E_0 \sin(kx-\omega t); ~B_z= B_0\sin(kx-\omega t),\) then:
1. \(E_0k=B_0\omega\)
2. \(E_0B_0 = \omega k\)
3. \(E_0\omega= B_0k\)
4. \(E_0B_0= \frac{\omega}{k}\)
A charged particle oscillates about its mean equilibrium position with a frequency of \(10^9 \text{ Hz}\). The electromagnetic waves produced:
(a) | will have frequency of \(2×10^9 \text{ Hz}\) |
(b) | will have frequency of \(10^9 \text{ Hz}\) |
(c) | will have wavelength of \(0.3\) m |
(d) | fall in the region of radiowaves |
Choose the correct options:
1. | (a), (b), (c) | 2. | (a), (c), (d) |
3. | (b), (c), (d) | 4. | (c), (d) |
The source of electromagnetic waves can be a charge:
(a) | moving with a constant velocity |
(b) | moving in a circular orbit |
(c) | at rest |
(d) | falling in an electric field |
An EM wave of intensity \(I\) falls on a surface kept in a vacuum and exerts radiation pressure \(P\) on it. Which of the following are true?
(a) | Radiation pressure is \(\frac{I}{c}\) if the wave is totally absorbed. |
(b) | Radiation pressure is \(\frac{I}{c}\) if the wave is totally reflected. |
(c) | Radiation pressure is \(\frac{2I}{c}\) if the wave is totally reflected. |
(d) | Radiation pressure is in the range \(\frac{I}{c}<P<\frac{2I}{c}\) for real surfaces. |
Choose the correct one from the given options:
1. | a, b and c | 2. | b, c and d |
3. | a, c and d | 4. | c and d |
One requires \(11\) eV of energy to dissociate a carbon monoxide molecule into carbon and oxygen atoms. The minimum frequency of the appropriate electromagnetic radiation to achieve the dissociation lies in:
1. visible region
2. infrared region
3. ultraviolet region
4. microwave region
A linearly polarised electromagnetic wave given as is incident normally on a perfectly reflecting infinite wall at z = a. Assuming that the material of the wall is optically inactive, the reflected wave will be given as:
1.
2.
3.
4.
Light with an energy flux of \(20~\text{W/cm}^2\) falls on a non-reflecting surface at normal incidence. If the surface has an area of \(30~\text{cm}^2\), the momentum delivered (for complete absorption) during \(30\) minutes is:
1. \(36\times10^{-5}~\text{kg-m/s}\)
2. \(36\times10^{-4}~\text{kg-m/s}\)
3. \(108\times10^{4}~\text{kg-m/s}\)
4. \(1.08\times10^{7}~\text{kg-m/s}\)
The electric field produced by the radiations coming from \(100~\text{W}\) bulb at a \(3~\text{m}\) distance is \(E\). The electric field intensity produced by the radiations coming from \(50~\text{W}\) bulb at the same distance is:
1. \(\dfrac{E}{2}\)
2. \(2E\)
3. \(\dfrac{E}{\sqrt2}\)
4. \(\sqrt2E\)
If E and B represent electric and magnetic field vectors of the electromagnetic wave, the direction of propagation of the electromagnetic wave is along:
1. E
2. B
3. B x E
4. E x B
The ratio of contributions made by the electric field and magnetic field components to the intensity of an EM wave is:
1. c : 1
2. : 1
3. 1 : 1
4. : 1