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.