UNIT 1 SPCM

What does conductivity of metals depend upon?

• The nature of the material

• Number of free electrons

• Resistance of the metal

• Number of electrons

What happens to the free electrons when electric field is applied?

• They move randomly and collide with each other

• They move in the direction of the field

• They remain stable

• They move in the direction opposite to that of the field

Outer most shell of atom with highest energy level is known as

• 1st shell

• 2nd shell

• Valence shell

• hole shell

Which of the following theories cannot be explained by classical theory?

• Electron theory

• Lorentz theory

• Photo-electric effect

• Classical free electron theory

Which of the following theories can be adopted to rectify the drawbacks of classical theory?

• Compton theory

• Quantum theory

• Band theory

• Electron theory

How does a semiconductor behave at absolute zero?

• Conductor

• Insulator

• Semiconductor

• Protection device

What are the charge carriers in semiconductors?

• Electrons and holes

• Electrons

• Holes

• Charges

How is charge carriers produced in intrinsic semiconductors?

• By pure atoms

• By electrons

• By impure atoms

• By holes

What type of material is obtained when intrinsic semiconductor is doped with pentavalent impurity?

• N-type semiconductor

• Extrinsic semiconductor

• P-type semiconductor

• Insulator

What type of material is obtained when an intrinsic semiconductor is doped with trivalent impurity?

• Extrinsic semiconductor

• Insulator

• N-type semiconductor

• P-type semiconductor