Advertisements
Advertisements
प्रश्न
Optical and radio telescopes are built on the ground but X-ray astronomy is possible only from satellites orbiting the earth. Why?
Advertisements
उत्तर
With reference to X-ray astronomy, X-rays are absorbed by the atmosphere. However, visible and radio waves can penetrate it. Hence, optical and radio telescopes are built on the ground, while X-ray astronomy is possible only with the help of satellites orbiting the Earth.
संबंधित प्रश्न
Give a reason for the following:
It is necessary to use satellites for long-distance TV transmission. Why?
What do you understand by the invisible spectrum?
Characteristic X-rays may be used to identify the element from which they are being emitted. Can continuous X-rays be used for this purpose?
Is it possible that in a Coolidge tube characteristic Lα X-rays are emitted but not Kα X-rays?
If the current in the circuit for heating the filament is increased, the cutoff wavelength
Moseley's Law for characteristic X-ray is √v = a(Z − b). Here,
Visible light passing through a circular hole forms a diffraction disc of radius 0.1 mm on a screen. If an X-ray is passed through the same setup, the radius of the diffraction disc will be
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.)
To which regions of the electromagnetic spectrum do the following wavelengths belong:
(a) 250 nm
(b) 1500 nm
Calculate the shortest wavelength of electromagnetic radiation present in Balmer series of hydrogen spectrum.
Name the radiation of the electromagnetic spectrum which is used for the following:
To photograph internal parts of the human body and Give the frequency range
State two properties of infrared radiations which differ from visible light.
Give one use of electromagnetic radiation in Microwaves.
Give one use of electromagnetic radiations in Infrared radiation.
Answer briefly.
Does an ordinary electric lamp emit EM waves?
Answer briefly.
Why light waves travel in a vacuum whereas sound waves cannot?
Solve the numerical problem.
Calculate the wavelength in nm of an X-ray wave of frequency 2.0 × 1018 Hz.
Name the e.m. waves which are suitable for radar systems used in aircraft navigation. Write the range of frequency of these waves.
Which of the following is a tool used for separating the different color wavelengths from each other?
SONAR emits which of the following waves?
