All Courses
Explore Courses UPSC Exam UPSC Test Series Free Notes EduRev Infinity Get the App Login Join for Free
Sign in Open App
Class 12 Exam  >  Class 12 Questions  >  In a pure, or intrinsic, semiconductor, valen... Start Learning for Free
In a pure, or intrinsic, semiconductor, valence band holes and conduction-band electrons are always present
  • a)
    such that number of holes is greater than the number of electrons
  • b)
    in equal numbers
  • c)
    such that number of electrons is greater than the number of holes
  • d)
    none of these
Correct answer is option 'B'. Can you explain this answer?
Clear all your Class 12 doubts with EduRev
Verified Answer
In a pure, or intrinsic, semiconductor, valence band holes and conduct...
Explanation:An intrinsic semiconductor, also called an undoped semiconductor or i-type semiconductor, is a pure semiconductor without any significant dopant species present. The number of charge carriers is therefore determined by the properties of the material itself instead of the amount of impurities. In intrinsic semiconductors the number of excited electrons and the number of holes are equal: n = p.
View all questions of this test
Most Upvoted Answer
In a pure, or intrinsic, semiconductor, valence band holes and conduct...
Understanding Intrinsic Semiconductors
In intrinsic semiconductors, the behavior of charge carriers is fundamental to their electronic properties. Here’s a detailed explanation of why the number of holes equals the number of electrons.
Charge Carriers in Semiconductors
- Electrons and Holes: In a semiconductor, electrons can move freely in the conduction band, while holes (the absence of an electron) exist in the valence band.
- Intrinsic Nature: Intrinsic semiconductors are pure materials without any significant impurities. The electrons in the conduction band come from the valence band when thermal energy breaks the covalent bonds.
Equal Numbers of Electrons and Holes
- Generation of Electron-Hole Pairs: When an electron is excited from the valence band to the conduction band, it leaves behind a hole. This process ensures that for every electron promoted to the conduction band, there is a corresponding hole created in the valence band.
- Thermal Equilibrium: In an intrinsic semiconductor at thermal equilibrium, the generation of electron-hole pairs is balanced by their recombination. Hence, the number of electrons (n) in the conduction band equals the number of holes (p) in the valence band, leading to the equation n = p.
Conclusion
- The intrinsic nature of semiconductors guarantees that the number of conduction electrons and valence band holes are equal. This balance is a defining characteristic of pure semiconductors, making option 'B' (in equal numbers) the correct answer.
Understanding this fundamental concept is crucial for grasping the behavior of semiconductors in electronic devices.
Explore Courses for Class 12 exam

Similar Class 12 Doubts

Read the following text and answer the following questions on the basis of the same:Electron Microscope Electron microscopes use electrons to illuminate a sample. In Transmission Electron Microscopy (TEM), electrons pass through the sample and illuminate film or a digital camera.Resolution in microscopy is limited to about half of the wavelength of the illumination source used to image the sample. Using visible light the best resolution that can be achieved by microscopes is about ~200 nm. Louis de Broglie showed that every particle or matter propagates like a wave. The wavelength of propagating electrons at a given accelerating voltage can be determined byThus, the wavelength of electrons is calculated to be 3.88 pm when the microscope is operated at 100 keV, 2. 74 pm at 200 keV and 2.24 pm at 300 keV. However, because the velocities of electrons in an electron microscope reach about 70% the speed of light with an accelerating voltage of 200 keV, there are relativistic effects on these electrons. Due to this effect, the wavelength at 100 keV, 200 keV and 300 keV in electron microscopes is 3.70 pm, 2.51 pm and 1.96 pm, respectively.Anyhow, the wavelength of electrons is much smaller than that of photons (2.5 pm at 200 keV). Thus if electron wave is used to illuminate the sample, the resolution of an electron microscope theoretically becomes unlimited. Practically, the resolution is limited to ~0.1 nm due to the objective lens system in electron microscopes. Thus, electron microscopy can resolve subcellular structures that could not be visualized using standard fluorescences microscopy.Q. Why electron as wave is used in electron microscope to illuminate the sample?

Read the following text and answer the following questions on the basis of the same:Electron Microscope Electron microscopes use electrons to illuminate a sample. In Transmission Electron Microscopy (TEM), electrons pass through the sample and illuminate film or a digital camera.Resolution in microscopy is limited to about half of the wavelength of the illumination source used to image the sample. Using visible light the best resolution that can be achieved by microscopes is about ~200 nm. Louis de Broglie showed that every particle or matter propagates like a wave. The wavelength of propagating electrons at a given accelerating voltage can be determined byThus, the wavelength of electrons is calculated to be 3.88 pm when the microscope is operated at 100 keV, 2. 74 pm at 200 keV and 2.24 pm at 300 keV. However, because the velocities of electrons in an electron microscope reach about 70% the speed of light with an accelerating voltage of 200 keV, there are relativistic effects on these electrons. Due to this effect, the wavelength at 100 keV, 200 keV and 300 keV in electron microscopes is 3.70 pm, 2.51 pm and 1.96 pm, respectively.Anyhow, the wavelength of electrons is much smaller than that of photons (2.5 pm at 200 keV). Thus if electron wave is used to illuminate the sample, the resolution of an electron microscope theoretically becomes unlimited. Practically, the resolution is limited to ~0.1 nm due to the objective lens system in electron microscopes. Thus, electron microscopy can resolve subcellular structures that could not be visualized using standard fluorescences microscopy.Q. As the accelerating voltage increases, the wavelength of electron as wave

Read the following text and answer the following questions on the basis of the same:Electron Microscope Electron microscopes use electrons to illuminate a sample. In Transmission Electron Microscopy (TEM), electrons pass through the sample and illuminate film or a digital camera.Resolution in microscopy is limited to about half of the wavelength of the illumination source used to image the sample. Using visible light the best resolution that can be achieved by microscopes is about ~200 nm. Louis de Broglie showed that every particle or matter propagates like a wave. The wavelength of propagating electrons at a given accelerating voltage can be determined byThus, the wavelength of electrons is calculated to be 3.88 pm when the microscope is operated at 100 keV, 2. 74 pm at 200 keV and 2.24 pm at 300 keV. However, because the velocities of electrons in an electron microscope reach about 70% the speed of light with an accelerating voltage of 200 keV, there are relativistic effects on these electrons. Due to this effect, the wavelength at 100 keV, 200 keV and 300 keV in electron microscopes is 3.70 pm, 2.51 pm and 1.96 pm, respectively.Anyhow, the wavelength of electrons is much smaller than that of photons (2.5 pm at 200 keV). Thus if electron wave is used to illuminate the sample, the resolution of an electron microscope theoretically becomes unlimited. Practically, the resolution is limited to ~0.1 nm due to the objective lens system in electron microscopes. Thus, electron microscopy can resolve subcellular structures that could not be visualized using standard fluorescences microscopy.Q. In electron microscope, electron is used

In a pure, or intrinsic, semiconductor, valence band holes and conduction-band electrons are always presenta)such that number of holes is greater than the number of electronsb)in equal numbersc)such that number of electrons is greater than the number of holesd)none of theseCorrect answer is option 'B'. Can you explain this answer?
Question Description
In a pure, or intrinsic, semiconductor, valence band holes and conduction-band electrons are always presenta)such that number of holes is greater than the number of electronsb)in equal numbersc)such that number of electrons is greater than the number of holesd)none of theseCorrect answer is option 'B'. Can you explain this answer? for Class 12 2025 is part of Class 12 preparation. The Question and answers have been prepared according to the Class 12 exam syllabus. Information about In a pure, or intrinsic, semiconductor, valence band holes and conduction-band electrons are always presenta)such that number of holes is greater than the number of electronsb)in equal numbersc)such that number of electrons is greater than the number of holesd)none of theseCorrect answer is option 'B'. Can you explain this answer? covers all topics & solutions for Class 12 2025 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for In a pure, or intrinsic, semiconductor, valence band holes and conduction-band electrons are always presenta)such that number of holes is greater than the number of electronsb)in equal numbersc)such that number of electrons is greater than the number of holesd)none of theseCorrect answer is option 'B'. Can you explain this answer?.
Solutions for In a pure, or intrinsic, semiconductor, valence band holes and conduction-band electrons are always presenta)such that number of holes is greater than the number of electronsb)in equal numbersc)such that number of electrons is greater than the number of holesd)none of theseCorrect answer is option 'B'. Can you explain this answer? in English & in Hindi are available as part of our courses for Class 12. Download more important topics, notes, lectures and mock test series for Class 12 Exam by signing up for free.
Here you can find the meaning of In a pure, or intrinsic, semiconductor, valence band holes and conduction-band electrons are always presenta)such that number of holes is greater than the number of electronsb)in equal numbersc)such that number of electrons is greater than the number of holesd)none of theseCorrect answer is option 'B'. Can you explain this answer? defined & explained in the simplest way possible. Besides giving the explanation of In a pure, or intrinsic, semiconductor, valence band holes and conduction-band electrons are always presenta)such that number of holes is greater than the number of electronsb)in equal numbersc)such that number of electrons is greater than the number of holesd)none of theseCorrect answer is option 'B'. Can you explain this answer?, a detailed solution for In a pure, or intrinsic, semiconductor, valence band holes and conduction-band electrons are always presenta)such that number of holes is greater than the number of electronsb)in equal numbersc)such that number of electrons is greater than the number of holesd)none of theseCorrect answer is option 'B'. Can you explain this answer? has been provided alongside types of In a pure, or intrinsic, semiconductor, valence band holes and conduction-band electrons are always presenta)such that number of holes is greater than the number of electronsb)in equal numbersc)such that number of electrons is greater than the number of holesd)none of theseCorrect answer is option 'B'. Can you explain this answer? theory, EduRev gives you an ample number of questions to practice In a pure, or intrinsic, semiconductor, valence band holes and conduction-band electrons are always presenta)such that number of holes is greater than the number of electronsb)in equal numbersc)such that number of electrons is greater than the number of holesd)none of theseCorrect answer is option 'B'. Can you explain this answer? tests, examples and also practice Class 12 tests.
Explore Courses for Class 12 exam
SaveJoin the Discussion on the App for FREE
Signup for Free!
Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
10M+ students study on EduRev
Get App
© EduRev
Education Revolution
Signup to see your scores go up within 7 days!
Access 1000+ FREE Docs, Videos and Tests
Takes less than 10 seconds to signup