Advertisements
Advertisements
प्रश्न
A plane electromagnetic wave travels in vacuum along z-direction. What can you say about the directions of its electric and magnetic field vectors? If the frequency of the wave is 30 MHz, what is its wavelength?
Advertisements
उत्तर
The electromagnetic wave travels in a vacuum along the z-direction. The electric field (E) and the magnetic field (H) are in the x-y plane and mutually perpendicular.
Frequency of the wave, v = 30 MHz = 30 × 106 s−1
Speed of light in a vacuum, c = 3 × 108 m/s
Wavelength of a wave is given as:
`lambda = "c"/"v"`
= `(3 xx 10^8)/(30 xx 10^6)`
= 10 m
APPEARS IN
संबंधित प्रश्न
How are infrared waves produced?
Give a reason for the following:
Long-distance radio broadcasts use short-wave bands. Why?
The wavelengths for the light of red and blue colours are roughly 7.8 × `10^7` m and 4.8 × `10^7` m respectively.
(a) Which colour has the greater speed in vacuum?
(b) Which colour has the greater speed in glass?
What is the range of the wavelength of the following electromagnetic waves?
(a) Visible.
What are ultraviolet radiations?
Can Lα X-ray of one material have shorter wavelength than Kα X-ray of another?
The X-ray beam emerging from an X-ray tube
Find the cutoff wavelength for the continuous X-rays coming from an X-ray tube operating at 30 kV.
(Use Planck constant h = 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
What potential difference should be applied across an X-ray tube to get X-ray of wavelength not less than 0.10 nm? What is the maximum energy of a photon of this X-ray in joule?
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
Name the scientist who discovered radio waves
To which regions of the electromagnetic spectrum do the following wavelengths belong:
(a) 250 nm
(b) 1500 nm
State two properties of infrared radiations which differ from visible light.
Answer briefly.
What is a carrier wave?
Answer briefly.
Why high-frequency carrier waves are used for the transmission of audio signals?
Solve the numerical problem.
Calculate the wavelength in nm of an X-ray wave of frequency 2.0 × 1018 Hz.
Calculate the wavelength of a microwave of a frequency of 8.0 GHz.
Radio waves of constant amplitude can be generated with.
One requires 11eV 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 ______.
Arrange the following electromagnetic radiation in the ascending order of their frequencies:
X-rays, microwaves, gamma rays, radio waves
Give any two uses of infrared waves.
