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Light sources with a 21 cm wavelength correspond to the radio emissions from neutral hydrogen atoms, which are abundant in the universe. This wavelength allows astronomers to map the distribution and density of hydrogen gas in galaxies and interstellar space, providing insights into the structure and dynamics of the universe. Additionally, 21 cm radiation can penetrate dust clouds that obscure optical observations, enabling the study of regions otherwise hidden from view.
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How do scientists determine the chemical makeup of the stars?
Different chemicals emit and absorb light at various wavelengths. Astronomers can look at the wavelength of light coming from stars and determine which chemicals must be present.
Why is called as monocromatic source of light?
Mono chromatic light is emitted by a laser source or by a red Light Emitting Diode. These sources emit a single wavelength of light around 550 nanoMetres. White light from the sun for example is a mixture of many wavelengths mixed together from red to violet to form white light.
What is a sentence for wavelength?
The wavelength of a transverse wave is the distance between adjacent crests or troughs (peaks or valleys).
How determine surface temperature of a star?
The surface temperature of a star can be determined by analyzing its spectrum. Specifically, scientists can observe the peak wavelength of light emitted by the star and use Wien's Law, which relates the peak wavelength to the temperature of the emitting object. By measuring the peak wavelength, astronomers can calculate the surface temperature of the star.
What kind of spectrum do astronomers find most useful?
Astronomers find the electromagnetic spectrum most useful during their observations and research. This spectrum includes various types of radiation such as visible light, radio waves, X-rays, and gamma rays, which provide valuable information about the properties and behavior of celestial objects. By studying different wavelengths of light, astronomers can gain insights into the composition, temperature, and movement of objects in the universe.
What is the unit that astronomers most often use to express the wavelength of light?
Speed of light
Which forms of electromagnetic radiation can interfere with the work of astronomers?
Light pollution from urban areas and artificial sources like street lights can interfere with astronomers' ability to observe celestial objects clearly. Additionally, radio waves from telecommunications and other sources can disrupt radio telescopes that astronomers use to study the universe.
How do astronomers determine the speed at which a galaxy is moving?
By examining its spectrum, and identifying absorption lines in it. Lines are shifted toward shorter wavelength if the object is moving towards us. They're shifted toward longer wavelength if the object is moving away from us.
What is the wavelength of selenium?
The wavelength of selenium typically refers to the wavelength of light emitted by selenium when it is excited. Selenium emits light in the red part of the spectrum with a wavelength around 600-700 nanometers. This characteristic makes selenium useful in applications like photocopiers and photovoltaic cells.
Can light have a single wavelength?
Yes, light can have a single wavelength, which would correspond to a specific color in the visible spectrum. Different sources of light emit light with varying wavelengths, resulting in the various colors we perceive.
What is the need for fluorescent material?
Fluorescent materials are needed for a variety of applications such as lighting, bioimaging, and security features. These materials are able to absorb light at one wavelength and emit it at a different, longer wavelength, making them useful for creating efficient light sources, visualizing biological processes, and preventing counterfeiting.
What are coherent sources and conditions for it?
Coherent sources are sources that emit light waves with a constant phase relationship. Conditions for coherence include having the same frequency, wavelength, and waveform, as well as a constant phase difference between the sources. This coherence allows for interference effects to occur, resulting in patterns such as diffraction and interference fringes.
Is it possible to coherence between light sources emitting light of different wavelengths?
I don't think so. Coherence is defined for light of a single wavelength.
Which equipment is most useful when measuring wavelength?
A spectrophotometer is typically the most useful equipment for measuring wavelength. It can measure the absorbance or transmittance of a substance at different wavelengths, allowing for the determination of the wavelength of maximum absorbance or transmittance.
How do scientists determine the chemical makeup of the stars?
Different chemicals emit and absorb light at various wavelengths. Astronomers can look at the wavelength of light coming from stars and determine which chemicals must be present.
What is the formula for fringe width?
Fringe width (for dark and bright bands): D * wavelength / d where, D = distance between screen and coherent sources (metres), wavelength = wavelength of light used is experiment (nanometres), d = distance between the 2 coherent sources (millimetres).
By which law can temperature of stars be estimated?
The temperature of stars can be estimated using Wien's law, which states that the wavelength at which a star emits the most light is inversely proportional to its temperature. This relationship allows astronomers to analyze the peak wavelength of a star's spectrum to determine its temperature.
