When a conductor carries more current on the surface as compared to core, it is due to___________?

Related Mcqs:

1. The angular displacement between two interconnected stations is mainly due to___________?

   A. armature reactance of both alternators
   B. reactance of the interconnector
   C. synchronous reactance of both the alternators
   D. all of the above

2. A conductor, due to sag between two supports, takes the form of____________?

   A. semi-circle
   B. triangle
   C. ellipse
   D. catenary

3. jCorona usually occurs when the electrostatic stress in air around the conductor exceeds?

   A. 6.6 kV (r.m.s. value)/cm
   B. 11 kV (r.m.s. value)/cm
   C. 22 kV (maximum value)/cm
   D. 30 kV (maximum value)/cm

4. The skin effect of a conductor will reduce as the__________?

   A. resistivity of conductor material increases
   B. permeability of conductor material increases
   C. diameter increases
   D. frequency increases

5. When a live conductor of public electric supply breaks down and touches the earth which of the following will happen?

   A. Current will flow to earth
   B. Supply voltage will drop
   C. Supply voltage will increase
   D. No current will flow in the conductor
   E. None of the above

6. If variable part of annual cost on account of interest and depreciation on the capital outlay is equal to the annual cost of electrical energy wasted in the conductors, the total annual cost will be minimum and the corresponding size of conductor will be most economical. This statement is known as___________________?

   A. Kelvin’s law
   B. Ohm’s law
   C. Kirchhoffs law
   D. Faraday’s law
   E. none of the above

7. In aluminium conductors, steel core is provided to____________?

   A. compensate for skin effect
   B. neutralise proximity effect
   C. reduce line inductance
   D. increase the tensile strength

8. The current drawn by the line due to corona losses is___________?

   A. non-sinusoidal
   B. sinusoidal
   C. triangular
   D. square

9. A uniformly-loaded D.C. distributor is fed at both ends with equal voltages. As compared to a similar distributor fed at one end only, the drop at the middle point is______________?

   A. one-fourth
   B. one-third
   C. one-half
   D. twice
   E. none of the above

10. As compared to a 2-wire D.C. distributor, a 3-wire distributor with same maximum voltage to earth uses only__________________?

    A. 31.25 percent of copper
    B. 33.3 percent of copper
    C. 66.7 percent of copper
    D. 125 percent of copper