Explain the energy bands in solids.
Explain the energy bands in solids.
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Solution and Explanation
1. Valence Band: The energy band filled with the highest energy electrons in a solid.
2. Conduction Band: The energy band above the valence band where electrons can move freely, contributing to conductivity.
3. Forbidden Energy Gap: The region between the valence band and conduction band where no electron can exist. Classification of solids based on band theory:
- Conductors: Overlapping valence and conduction bands.
- Semiconductors: Small energy gap between valence and conduction bands.
- Insulators: Large energy gap, preventing electron movement.
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Differentiate between interference and diffraction of light. Explain qualitatively the diffraction phenomenon of light by a single slit. Light of 6000 Ã… wavelength is incident normally on a single slit of width \( 3 \times 10^{-4} \, \text{cm} \). Find out the angular width of the central maxima.
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