search
person

1 Answer

When a conductor carries more current on the surface as compared to core, it is due to skin effect.

thumb_up_alt 0 like thumb_down_alt 0 dislike

Related questions

Description : When electric current passes through a metallic conductor, its temperature rises. This is due to?

Answer : When electric current passes through a metallic conductor, its temperature rises. This is due to collisions between conduction electrons and atoms.

Description : Heat in a conductor is produced on the passage of electric current due to?

Answer : Heat  in  a   conductor  is  produced   due  to  frictional  collision  of  electrons   flow  as  they  conduct  current.

Description : Explain the suitability of aluminium as an electrical conductor with respect to its mechanical and electrical properties. 

Answer : Following are requirements of conductor:- i) High conductivity :  Material should have high conductivity, So that * cross section of conductor (size) reduces, * Copper losses reduces, * So Efficiency ... . Boiling point is 1820°C 9. Specific gravity is 2.7 10. High resistance to corrosion. 

Description : When secondary of a current transformer is open-circuited its iron core will be?

Answer : When secondary of a current transformer is open-circuited its iron core will be hot because of heavy iron losses taking place in it due to high flux density.

Description : How does the resistance of a conductor compare to that of an insulator?

Answer : The resistance of a conductor can be significantly lower than the resistance of an insulator, depending on each material's atomic properties.

Description : The insulation on a current carrying conductor is provided?

Answer : The insulation on a current carrying conductor is provided to prevent leakage of current, to prevent shock.

Description : A ferrite core has less eddy current loss than an iron core because?

Answer : A ferrite core has less eddy current loss than an iron core because ferrites have high hysteresis.

Description : Current velocity through a copper conductor is

Description : Source transformation voltage source to current source and vice versa

Description : Explain why potential difference is necessary to produce current in a circuit.

Description : How to find total impedance Z, current I and Impedance angle ?

Answer : How to find total impedance Z, current I and Impedance angle ?

Description : Is Aluminium a good conductor of electricity?

Answer : Yes aluminium is a conductor and it is a good conductor of electricity. But copper have better conductivity as compare to aluminium.

Description : Why ACSR conductor is used for overhead lines?

Answer : It has high tensile strength 

Answer : In main line service as compared to urban and suburban service distance between the stops is more, maximum speed reached is high, acceleration and retardation rates are low.

Answer : A.C. series motor as compared to D.C. series motor has smaller brush width, less number of field turns, more number of armature turns, less air gap.

Answer : An alternator coupled to a hydraulic turbine runs at slow speed, as compared to others.

Answer : H.R.C. fuse, as compared to a rewirable fuse, has no ageing effect, high speed of operation, high rupturing capacity.

Description : In an alternator at lagging power factor the generated voltage per phase as compared to that at unity power factor?

Answer : In an alternator, at lagging power factor the generated voltage per phase as compared to that at unity power factor must be more than terminal voltage.

Description : Ferranti Effect is more pronounced when ___________ A) the line is longer and the voltage applied is higher B) the line is shorter and the voltage applied is lower C) the line is shorter and the voltage applied is higher D) none of these

Answer : Ferranti Effect is more pronounced when the line is longer and the voltage applied is higher

Description : Define surface tension. State its S.I. unit.

Answer : Definition:- The force acting per unit length of an imaginary line drawn to surface of liquid.  OR  The surface tension is defined as the property of liquids by virtue of which the surface of a liquid is ... due to the tendency to contract and occupy minimum surface area.  S.I. unit :- N/m

Description : State the significance of following terms : i) Hydrology ii) Surface run-off iii) Evaporation iv) Precipitation

Answer : (i) Hydrology: It may be defined as the science which deals with the depletion and replenishment of water resources. Hydrology deals with the occurrence and distribution of water over and under earth's ... types:  a) Liquid precipitation (Rainfall)  b) Solid precipitation (Snow, Hail) 

Description : In an AC. circuit, a low value of kVAR compared with kW indicates?

Answer : In an AC. circuit, a low value of kVAR compared with kW indicates high power factor.

Description : About trnsformer

Answer : Acc to Ohms law V=IR but it is only applicable when our resistance R is constant, as in case of transformer we take impedence which is equivalent to resistance is not constant it varies with system parameters that why Ohms law not applicable in case of transformer

Description : The size of a transformer core will depend on?

Answer : The size of a transformer core will depend on frequency and area of the core.

Description : Which is more temperature stable, a carbon-composition or a metal-film resistor? 

Description : Which have more free electrons: conductors or insulators? 

Answer : Conductors have many free electrons whereas insulators have very few or none at all.

Description : The resistance of a conductor varies inversely as?

Answer : The resistance of a conductor varies inversely as area of cross-section.

Description : The thickness of insulation provided on the conductor depends on?

Answer : The thickness of insulation provided on the conductor depends on the magnitude of voltage on the conductor.

Description : A single core lead sheathed cable with two dielectrics of permittivity 4 and 3, respectively, are subjected to same maximum stress. If the conductor diameter is 1.5 cm, the outer diameter of the first dielectric is (A) 1.125 cm (B) 1.5 cm (C ) 2 cm (D) 8 cm

Answer : A single core lead sheathed cable with two dielectrics of permittivity 4 and 3, respectively, are subjected to same maximum stress. If the conductor diameter is 1.5 cm, the outer diameter of the first dielectric is 2 cm 

Description : A single core cable is designed to work for a single phase system with a peak voltage of 220 kV. The maximum permissible stress in the dielectric is not to exceed 20 kV/mm. For economical size, the overall core diameter of the cable is (A) 28.2 mm (B) 26.4 mm (C) 24.4 mm (D) 22.0 mm

Answer : A single core cable is designed to work for a single phase system with a peak voltage of 220 kV. The maximum permissible stress in the dielectric is not to exceed 20 kV/mm. For economical size, the overall core diameter of the cable is 22.0 mm

Description : The main purpose of using core in a transformer is to (A) decrease iron losses (B) eliminate magnetic hysteresis (C) reduce reluctance of the common magnetic circuit (D) prevent eddy current loss

Answer : Reduce Relucatnce of the common magnetic circuit.

Description : Why does the core of a transformer need to be laminated?

Answer : Transformer cores are laminated to reduce eddy current loss.

Description : State the material used for making (1) Magnetic Core (2) Fuse element  

Answer : The material used for making of:  (1) Magnetic Core : Iron, cobalt, Nickel, CRGO, HRGO , silicon steel  (2) Fuse Element: Tin- lead wire, Tinned copper wire 

Description : State any four characteristics of core type transformer.

Answer : Characteristics of core type transformer: i) It has one window. ii) It has one magnetic circuit. iii) Core surrounds the winding. iv) Average length of core is more. v) Area of cross ... Better cooling for winding. vii) Mechnical strength is comparatively less. viii) Repair and maintenance is easy.

Description : A 40 kVA transformer has a core loss of 400 W and a full load copper loss of 800 W. The proportion of full load at maximum efficiency is

Answer : A 40 kVA transformer has a core loss of 400 W and a full load copper loss of 800 W. The proportion of full load at maximum efficiency is 0.707

Description : The core construction is like spokes of a wheel in following transformer:  (A) Berry Type Transformer (B) Core Type Transformer (C) Shell Type Transformer (D) None of the above

Answer : The core construction is like spokes of a wheel in following transformer:  Berry Type Transformer

Description : Core type transformers are popular in___________.  (A) High voltage applications (B) Low voltage applications (C) All of the above (D) None of the above

Answer : Core type transformers are popular in High voltage applications

Description : The desirable properties of transformer core material are  (1) low permeability and low hysteresis loss. (2) high permeability and high hysteresis loss. (3) high permeability and low hysteresis loss. (4) low permeability and hysteresis loss.

Answer : The desirable properties of transformer core material are high permeability and low hysteresis loss.

Answer : The armature core of a D.C. generator is usually made of silicon steel.

Answer : Material used for construction of transformer core is usually silicon steel.

Description : Reduction in core losses and increase in permeability are obtained with transformer employing?

Answer : Reduction in core losses and increase in permeability are obtained with transformer employing core built-up of laminations of cold rolled grain oriented steel.

Description : In DC generators lamination core are generally made of?

Answer : In DC generators lamination core are generally made of silicon steel.

Answer : Transformer core is laminated to reduce Eddy current losses.

Description : lf the wire which is vertical to this page has electron flow downwards the conductor will have

Answer : lf the wire which is vertical to this page has electron flow downwards the conductor will have a counter-clockwise field in the plane of the paper

Description : State properties of conductor material used for overhead conductor. 

Answer : Following are the properties of conductor material:-   1. High conductivity :- Material should have high conductivity 2. High mechanical strength:- Material should have sufficiently high mechanical strength ... available & less costly. 9. Scrap Value: - Material should have high scrap value. 

Answer : Which allows the flow electrons 

Description : reasons the transposition of conductor

Answer : Following reasons the transposition of conductor:  1. Due transposition of conductor inductance of each line is same LA = LB = LC, So drop due to inductive reactance in each line is same so ... interferences are less due to transposition.  Figure of transposition of conductor: 

Description : What is difference between Conductor and insulator ?

Answer : Conductor is a material that offers no resistance to the flow of current, while an insulator is a material that offers total resistance to the flows of current, It doesn't allowed any flows of current.

Description : What is the difference between a cable and a conductor?

Description : Which is the best conductor: silver, carbon, or iron?

Answer : Silver is the best conductor. Carbon is the semiconductor. Iron have less conductance as compared to silver.

← Prev Question Next Question →
editChoose topic
...