A. Both have great tendency for oxidation
B. Both have low melting point
C. Very large length of wires will be required
D. All of the above
Related Mcqs:
- Due to which of the following reasons aluminium does not corrode in atmosphere ?
A. Aluminium is a noble metal
B. Atmospheric oxygen can only diffuse very slowly through the oxide layer which is formed on the surface of aluminium
C. No reaction with oxygen occurs ft Any of the above - Due to which of the following fact, in India, aluminium is replacing copper ?
A. Aluminium is more ductile and malleable than copper
B. Aluminium is available in plenty, cheaper and lighter than copper
C. Aluminium has lower resistivity than that of copper
D. Aluminium has less temperature co-efficient than copper - Which of the following variety of copper has the best conductivity ?
A. Induction hardened copper
B. Hard drawn copper
C. Pure annealed copper
D. Copper containing traces of silicon - Copper, even though costly, finds use in the windings of electrical machines because_____________?
A. copper points offer low contact resistance
B. copper can be easily soldered and welded
E. copper windings are less bulky and the machines become compact
D. all of the above - Due to which of the following factors the brush wear rate is altered ?
A. Speed of the machine
B. Contact pressure
C. Surface conditions of brush and commutator
D. Excessive sparking
E. All of the above - The conductors have transport phenomena of electrons due to____________?
A. electric field
B. magnetic field
C. electromagnetic field
D. none of the above - The conduction of electricity, in semiconductors, takes place due to movement of______________?
A. positive ions only
B. negative ions only
C. positive and negative ions
D. electrons and holes - In conductors conduction of electricity takes place due to movement of_______________?
A. electrons only
B. positive ions only
C. negative ions only
D. positive and negative ions
E. none of the above - Surface resistance of an insulating material is reduced due to the______________?
A. smoky and dirty atmosphere
B. humidity in the atmosphere
C. both (A) and (b)
D. neither (A) nor (b) - The current due to electron flow in conduction band is the hole current in valence band?
A. equal to
B. less than
C. greater than
D. any of the above
