Q. Statement 1 : The conductivity of a semiconductor increases with rise of temperature
Statement 2 : On rising temperature covalent bonds of semiconductor break

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Solution:

At , all semiconductors are insulators. The valence band at is completely filled and there are no free electrons in conduction band. At room temperature due to thermal energy, the electron jump to the conduction band. When the temperature increases, a large number of electrons cross over the forbidden gap and jump from valence band to conduction band. Thus with rise in temperature conductivity increases. The covalent bonds of semiconductor breaks only when it is heated up extremely either by increase in temperature or by supplying strong current. After which it behaves like conductor and no longer possesses the property of low conduction, hence it is said to be damaged