Engineering Materials Objectives Part 01
01 . Silver” has the highest electrical conductivity.
02 . Resistivity of metals is expressed in term of “μ ohm”.
03 . Resistivity of copper is of the order of “1.56 μ ohm-cm”.
04 . Resistivity of copper at absolute zero is “negligibly small”.
05 . A copper conductor of one square millimeter can safely carry a current of “10A”.
06 . For carrying an electric current of 75 A an aluminium conductor should have
minimum cross section of “25 mm2”.
07 . The atomic radius in case of face centred cubic lattice is “a/2”.
08 . Pure annealed” variety of copper has the best conductivity.
09 . Hard drawn” variety of copper has the best mechanical strength.
10 . Aluminium core is known “bauxite”.
11 . Carbon” has the negative resistance temperature coefficient.
12 . Nickel is used in “electrodes of the thermionic valves”.
13 . “Lead” can be used for making cable sheaths.
14 . Application of tin is in “low current fuses”.
15 . Constantan contains “copper and nickel”.
16 . German silver is an alloy of “Copper, Zinc and Nickel”.
17 . Nichrome is an alloy of “Nickel, Chromium and Iron”.
18 . The resistance of conductor does not vary in accordance with the Ohm’s laws it is known as “Non-linear conductor”.
19 . If a body has identical properties all over, it is knownas “Homogeneous”.
20 . The atomic radius in case of body centred lattice is “a.
