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321.

The resistivity of electrical conductors is most affected by

322.

Line imperfection in a crystal is called

323.

Selenium is

324.

Which of the following is p-type semi-conductor?

A.	Selenium	B.	Silicon doped with phosphorous
C.	Silicon doped with gallium	D.	All of the above
E.	None of the above

325.

The electrical resistance of a semi-conductor

A.	Increases with temperature	B.	Decreases with temperature
C.	Does not change with temperature

326.

The semi-conductors have electrical conductivities of the following order (ohm-cm-1)

A.	10?20	B.	10?15
C.	10?3

327.

Polystrene at room temperature is

A.	Brittle	B.	Malleable
C.	Ductile	D.	Soft

328.

Which of the following method cannot be used for thermoplastic materials?

A.	Extrusion	B.	Blow moulding
C.	Injection moulding	D.	All of the above

329.

Which of the following method can be used for thermoplastic materials?

A.	Blow moulding	B.	Casting
C.	Calendering	D.	Compression moulding

330.

Plastic are

A.	Good conductors of heat and bad conductors of electricity	B.	Bad conductors of heat and good conductors of electricity
C.	Good conductors of heat as well as electricity	D.	Bad conductors of heat as well as electricity
E.	Semi-conductors