Multicore cables generally use________________?

Which of the following materials is used for overhead transmission lines ?

A. Steel cored aluminium
B. Galvanised steel
C. Cadmium copper
D. Any of the above

When an alternator connected to the bus-bar is shut down the bus-bar voltage will___________?

A. fall
B. rise
C. remain unchanged
D. none of the above

Aluminium has a specific gravity of___________?

A. 1.5
B. 2.7
C. 4.2
D. 7.8

Which of the following is the demerit of a ‘constant voltage transmission system’ ?

A. Increase of short-circuit current of the system
B. Availability of steady voltage at all loads at the line terminals
C. Possibility of better protection for the line due to possible use of higher terminal reactants
D. Improvement of power factor at times of moderate and heavy loads
E. Possibility of carrying increased power for a given conductor size in case of long-distance heavy power transmission

By which of the following a bus-bar is rated?

A. Current only
B. Current and voltage
C. Current, voltage and frequency
D. Current, voltage, frequency and short time current

For aluminium, as compared to copper, all the following factors have higher values except:

A. specific volume
B. electrical conductivity
C. co-efficient of linear expansion
D. resistance per unit length for same cross-section