We find, for a required current carrying capacity, aluminium conductor is larger in cross sectional area than copper. The reason for this is

26) 7/1.40 is the specification of the one stranded conductor. What does the denominator indicate in the above specification ?

27) The material that have only few electrons and are incapable of flowing current is

28) Which one of the following materials is the insulating material ?

29) Which of the following material is NOT a good insulator ?