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Statement-1 : When the temperature of a ...

Statement-1 : When the temperature of a semiconductor is increased, then its resistance decreases.
Statement-2 : The energy gap between conduction band and valence band is very small for semiconductor.

A

Statement-1 is true, Statement-2 is true, Statement-2 is a correct explanation of Statement-1.

B

Statement-1 is true, Statement-2 is true, Statement-2 is not a correct explanation of Statement-1.

C

Statement-1 is true, Statement-2 is false.

D

Statement-1 is false, Statement-2 is true.

Text Solution

Verified by Experts

The correct Answer is:
A
When temprature of semiconductor is raised, more covalent bonds are broken. Due to it, large number of electrons and holes are produced in semicoductor. Some electrons move from valence band to conduction band crossing over a very small energy gap and become free electrons. As a result of which the conductivity of semiconductor increases and hence resistance of semiconductor decreases.
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Knowledge Check

  • Assertion: If the temperature of a semiconductor is increased then its resistance decreases. Reason: The energy gap between conduction band and valence band is very small

    A
    If both the assertion and reason are true and reason is a true explantion of the assertion.
    B
    If both the assertion and reason are true but the reason is not true the correct explantion of the assertion.
    C
    If the assertion is true but reason false
    D
    If both the assertion and reason are false.

  • Assertion (A): As the temperature of a semiconductor increases, its resistance decreases. Reason (R ): The energy gap between conduction band and valence band is small.

    A
    Both A and R are true and R is the correct explanation of A
    B
    Both A and R are true but R is NOT the correct explanation of A
    C
    A is true but R is false
    D
    A is false and R is true

  • The gap between the conduction band and valence band is largest in

    A
    Semiconductors
    B
    Insulators
    C
    Conductors
    D
    None of the above

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