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प्रश्न
Write a short note on the visible spectrum.
उत्तर
Visible spectrum is produced by incandescent bodies and also it is radiated by excited atoms in gases. The wavelength range is 4 x 10-7 m to 7 x 10-7 m and the frequency range is 7 x 1014 Hz to 4 x 1014Hz. It obeys the laws of reflection, refraction, interference, diffraction, polarization, photoelectric effect, and photographic action. It can be used to study the structure of molecules, the arrangement of electrons in external shells of atoms, and the sensation of our eyes.
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संबंधित प्रश्न
Write any two important properties of electromagnetic waves.
The amplitude of the magnetic field part of a harmonic electromagnetic wave in vacuum is B0 = 510 nT. What is the amplitude of the electric field part of the wave?
In a plane electromagnetic wave, the electric field oscillates sinusoidally at a frequency of 2.0 × 1010 Hz and amplitude 48 V m−1.
- What is the wavelength of the wave?
- What is the amplitude of the oscillating magnetic field?
- Show that the average energy density of the E field equals the average energy density of the B field.
[c = 3 × 108 m s−1]
Draw a sketch of linearly polarized em waves propagating in the Z-direction. Indicate the directions of the oscillating electric and magnetic fields.
Discuss the Hertz experiment.
Which of these mechanisms can be used to produce electromagnetic waves?
The magnetic field of a plane electromagnetic wave travelling in +ve z-direction is described by ______.
Poynting vectors S is defined as a vector whose magnitude is equal to the wave intensity and whose direction is along the direction of wave propagation. Mathematically, it is given by `S = 1/mu_0 E xx B`. Show the nature of S vs t graph.
Which of the following statement is NOT true about the properties of electromagnetic waves?
A plane electromagnetic wave of frequency 500 MHz is travelling in a vacuum along a y-direction.
At a particular point in space and time, `vec"B"` = 8.0 × 10-8 `hat"Z"`T. The value of the electric field at this point is ______.
(speed of light = 3 × 108 ms-1)
`hat x, hat y, hat z` are unit vectors along x, y, and Z directions.
