Answer:Introduction
To produce an emission spectrum of hydrogen, the hydrogen gas needs to be in a glowing gaseous form. This is because the emission spectrum of an element is produced when the electrons in the atoms of that element are excited to higher energy levels and then fall back to lower energy levels, emitting photons of specific wavelengths in the process.
Explanation
Glowing Gaseous FormWhen hydrogen gas is in a glowing gaseous form, the atoms are excited by an external energy source such as an electric discharge or a flame. This excitation causes the electrons in the hydrogen atoms to move to higher energy levels. As the excited electrons return to their original energy levels, they release energy in the form of photons. The photons emitted have specific wavelengths corresponding to the energy difference between the excited and ground states of the hydrogen atom.
Emission SpectrumThe emitted photons create a spectrum of discrete lines, known as an emission spectrum. These lines are unique to each element and can be used to identify the presence of that element. In the case of hydrogen, the emission spectrum consists of several series of lines, with each series corresponding to a different energy transition within the hydrogen atom.
Other OptionsThe other options mentioned in the question, such as cold and white light shining through, cool liquid form, and hot and white light shining through, are not suitable for producing an emission spectrum of hydrogen.
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Cold and white light shining through: White light is a combination of all visible wavelengths, and shining it through a cold hydrogen gas would not result in the emission of specific wavelengths characteristic of hydrogen.
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Cool liquid form: When hydrogen is in a cool liquid form, the atoms are not excited, and therefore, no emission spectrum is produced.
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Hot and white light shining through: Similar to the cold and white light scenario, shining white light through hot hydrogen gas would not produce specific wavelengths characteristic of hydrogen.
ConclusionIn conclusion, to produce an emission spectrum of hydrogen, the hydrogen gas must be in a glowing gaseous form. This allows for the excitation of the hydrogen atoms and the subsequent emission of photons with specific wavelengths, creating the characteristic emission spectrum of hydrogen.