Insulators perform which of the following functions? a) Conduction b) Convection c) Provide electrical insulation d) Allows current leakage at interfaces

Insulators perform which of the following functions?
a) Conduction
b) Convection
c) Provide electrical insulation
d) Allows current leakage at interfaces
by

1 Answer

Answer :

c) Provide electrical insulation
by

Related questions

The charge build up in the capacitor is due to which quantity? a) Conduction current b) Displacement current c) Convection current d) Direct current

Description : The charge build up in the capacitor is due to which quantity? a) Conduction current b) Displacement current c) Convection current d) Direct current

Last Answer : d) Direct current

Calculate the electric field when the conductivity is 20 units, electron density is 2.4 units and the velocity is 10m/s. Assume the conduction and convection current densities are same. a) 2.4 b) 4.8 c) 3.6 d) 1.2

Description : Calculate the electric field when the conductivity is 20 units, electron density is 2.4 units and the velocity is 10m/s. Assume the conduction and convection current densities are same. a) 2.4 b) 4.8 c) 3.6 d) 1.2

Last Answer : d) 1.2

The current flowing through an insulating medium is called a) Conduction b) Convection c) Radiation d) Susceptibility

Description : The current flowing through an insulating medium is called a) Conduction b) Convection c) Radiation d) Susceptibility

Last Answer : b) Convection

When you are making a high potential test on a piece of repaired electrical machinery, a rise in leakage current indicates ____________. A. good insulation B. bad insulation C. high insulation power factor D. a high slot discharge factor

Description : When you are making a high potential test on a piece of repaired electrical machinery, a rise in leakage current indicates ____________. A. good insulation B. bad insulation C. high insulation power factor D. a high slot discharge factor

Last Answer : Answer: B

The atmosphere is heated mainly by – (1) Insulation (2) Conduction (3) Radiation (4) Convection

Description : The atmosphere is heated mainly by – (1) Insulation (2) Conduction (3) Radiation (4) Convection

Last Answer : (3) Radiation Explanation: Changes in weather involve air movements, formation of clouds, and precipitation. Energy is needed to make all these things happen. That energy comes from the sun. Heat energy ... radiation. Hot bodies such as the sun radiate their energy mainly in the form of short waves.

Ocean currents are an example of – (1) convection (2) conduction (3) insulation (4) radiation

Description : Ocean currents are an example of – (1) convection (2) conduction (3) insulation (4) radiation

Last Answer : (1) convection Explanation: Heat is transferred by convection in numerous examples of naturally occurring fluid flow, such as: wind, oceanic currents, and movements within the Earth's atmosphere. ... transfer heat from the surplus to deficit heat zones and set the oceanic circulation in motion.

Upto the critical radius of insulation, added insulation, will (A) Increase the heat loss (B) Decrease heat loss and will have no effect beyond that (C) Decrease heat flux (D) Reduce convection heat loss compared to conduction heat less

Description : Upto the critical radius of insulation, added insulation, will (A) Increase the heat loss (B) Decrease heat loss and will have no effect beyond that (C) Decrease heat flux (D) Reduce convection heat loss compared to conduction heat less

Last Answer : Option B

An electroscope charged WITHOUT contacting a charged body is charged by: w) induction x) conduction y) convection z) insulation

Description : An electroscope charged WITHOUT contacting a charged body is charged by: w) induction x) conduction y) convection z) insulation

Last Answer : ANSWER: W -- INDUCTION

Ocean currents are an example of (1) convection (2) conduction (3) insulation (4) radiation

Description : Ocean currents are an example of (1) convection (2) conduction (3) insulation (4) radiation

Last Answer : convection

The battery has following three major functions to perform: a) To provide a source of current for engine starting, lighting and use of horn. b) To help control the voltage in the electrical system. c) To store the current produced by dynamo/alternator and to furnish the current d) all of the above. Ans. d

Description : The battery has following three major functions to perform: a) To provide a source of current for engine starting, lighting and use of horn. b) To help control the voltage in the electrical system. c ... the current produced by dynamo/alternator and to furnish the current d) all of the above. Ans. d

Last Answer : ans d

Find the electron density when convection current density is 120 units and the velocity is 5m/s. a) 12 b) 600 c) 24 d) 720

Description : Find the electron density when convection current density is 120 units and the velocity is 5m/s. a) 12 b) 600 c) 24 d) 720

Last Answer : c) 24

Calculate the convection current when electron density of 200 units is travelling at a speed of 12m/s. a) 16.67 b) 2400 c) 2880 d) 0.0

Description : Calculate the convection current when electron density of 200 units is travelling at a speed of 12m/s. a) 16.67 b) 2400 c) 2880 d) 0.0

Last Answer : b) 2400

The skin effect is a phenomenon observed in a) Insulators b) Dielectrics c) Conductors d) Semiconductors

Description : The skin effect is a phenomenon observed in a) Insulators b) Dielectrics c) Conductors d) Semiconductors

Last Answer : c) Conductors

Skin depth phenomenon is found in which materials? a) Insulators b) Dielectrics c) Conductors d) Semiconductors

Description : Skin depth phenomenon is found in which materials? a) Insulators b) Dielectrics c) Conductors d) Semiconductors

Last Answer : c) Conductors

Dielectric constant will be high in a) Conductors b) Semiconductors c) Insulators d) Superconductors

Description : Dielectric constant will be high in a) Conductors b) Semiconductors c) Insulators d) Superconductors

Last Answer : c) Insulators

The heated parts of an electrical machine dissipate heat into their surroundings by which of the following modes of heat dissipation ? (a) Conduction (b) Convection (c) Radiation (d) All ofthe above

Description : The heated parts of an electrical machine dissipate heat into their surroundings by which of the following modes of heat dissipation ? (a) Conduction (b) Convection (c) Radiation (d) All ofthe above

Last Answer : (d) All ofthe above

Find the loss tangent of a material with conduction current density of 5 units and displacement current density of 10 units. a) 2 b) 0.5 c) 5 d) 10

Description : Find the loss tangent of a material with conduction current density of 5 units and displacement current density of 10 units. a) 2 b) 0.5 c) 5 d) 10

Last Answer : b) 0.5

At high frequencies, which parameter is significant? a) Conduction current b) Displacement current c) Attenuation constant d) Phase constant

Description : At high frequencies, which parameter is significant? a) Conduction current b) Displacement current c) Attenuation constant d) Phase constant

Last Answer : b) Displacement current

Calculate the conduction current density when the resistivity of a material with an electric field of 5 units is 4.5 units. a) 22.5 b) 4.5/5 c) 5/4.5 d) 9.5

Description : Calculate the conduction current density when the resistivity of a material with an electric field of 5 units is 4.5 units. a) 22.5 b) 4.5/5 c) 5/4.5 d) 9.5

Last Answer : c) 5/4.5

The charge build up in a capacitor is due to a) Conduction current density b) Displacement current density c) Polarisation d) Magnetization

Description : The charge build up in a capacitor is due to a) Conduction current density b) Displacement current density c) Polarisation d) Magnetization

Last Answer : b) Displacement current density

The magnitude of the conduction current density for a magnetic field intensity of a vector yi + zj + xk will be a) 1.414 b) 1.732 c) -1.414 d) -1.732

Description : The magnitude of the conduction current density for a magnetic field intensity of a vector yi + zj + xk will be a) 1.414 b) 1.732 c) -1.414 d) -1.732

Last Answer : b) 1.732

Both the conduction and displacement current densities coexist in which medium? a) Only conductors in air b) Only dielectrics in air c) Conductors placed in any dielectric medium d) Both the densities can never coexist

Description : Both the conduction and displacement current densities coexist in which medium? a) Only conductors in air b) Only dielectrics in air c) Conductors placed in any dielectric medium d) Both the densities can never coexist

Last Answer : c) Conductors placed in any dielectric medium

Find the conduction current density of a material with conductivity 200units and electric field 1.5 units. a) 150 b) 30 c) 400/3 d) 300

Description : Find the conduction current density of a material with conductivity 200units and electric field 1.5 units. a) 150 b) 30 c) 400/3 d) 300

Last Answer : d) 300

When the conduction current density and displacement current density are same, the dissipation factor will be a) Zero b) Minimum c) Maximum d) Unity

Description : When the conduction current density and displacement current density are same, the dissipation factor will be a) Zero b) Minimum c) Maximum d) Unity

Last Answer : d) Unity

The ratio of conduction to displacement current density is referred to as a) Attenuation constant b) Propagation constant c) Loss tangent d) Dielectric constant

Description : The ratio of conduction to displacement current density is referred to as a) Attenuation constant b) Propagation constant c) Loss tangent d) Dielectric constant

Last Answer : c) Loss tangent

Find the conductivity of a material with conduction current density 100 units and electric field of 4 units. a) 25 b) 400 c) 0.04 d) 1600

Description : Find the conductivity of a material with conduction current density 100 units and electric field of 4 units. a) 25 b) 400 c) 0.04 d) 1600

Last Answer : a) 25

Find the conduction current density when conductivity of a material is 500 units and corresponding electric field is 2 units. a) 500 b) 250 c) 1000 d) 2000

Description : Find the conduction current density when conductivity of a material is 500 units and corresponding electric field is 2 units. a) 500 b) 250 c) 1000 d) 2000

Last Answer : c) 1000

The current in a metal at any frequency is due to a) Conduction current b) Displacement current c) Both conduction and displacement current d) Neither conduction nor displacement current

Description : The current in a metal at any frequency is due to a) Conduction current b) Displacement current c) Both conduction and displacement current d) Neither conduction nor displacement current

Last Answer : a) Conduction current

When a megohmmeter is used to test the insulation of a large motor, the initial dip of the pointer toward 'zero' is caused by ____________. A. good insulation B. the capacitance of the windings C. the leakage of the current along the surface of dirty insulation D. the dielectric-absorption effect of the insulation

Description : When a megohmmeter is used to test the insulation of a large motor, the initial dip of the pointer toward 'zero' is caused by ____________. A. good insulation B. the capacitance of the ... of the current along the surface of dirty insulation D. the dielectric-absorption effect of the insulation

Last Answer : Answer: B

When a megohmmeter is being used to test insulation resistance, current leakage along the surface of the insulation is indicated by the megohmmeter pointer _____________. A. fluctuating around a constant resistance reading B. dipping towards 'zero', then rising slowly C. kicking slightly downscale as voltage is applied D. continually rising as the test voltage is applied

Description : When a megohmmeter is being used to test insulation resistance, current leakage along the surface of the insulation is indicated by the megohmmeter pointer _____________. A. fluctuating around a ... slightly downscale as voltage is applied D. continually rising as the test voltage is applied

Last Answer : Answer: C

When using a megohmmeter to test the dielectric strength of wire insulation, a continuous series of slight downscale kicks by the pointer is result of ____________. A. good insulation B. the leakage of current along the surface of dirty insulation C. the capacitance of the windings D. the dielectric-absorption effect of the insulation

Description : When using a megohmmeter to test the dielectric strength of wire insulation, a continuous series of slight downscale kicks by the pointer is result of ____________. A. good insulation B. the ... dirty insulation C. the capacitance of the windings D. the dielectric-absorption effect of the insulation

Last Answer : Answer: B

When a megohmmeter is used to test the dielectric strength of wire insulation, the initial dip of the pointer toward 'zero' is caused by _____________. A. good insulation B. the leakage of current along the surface of dirty insulation C. the capacitance of the circuit D. the dielectric absorption effect of the insulation

Description : When a megohmmeter is used to test the dielectric strength of wire insulation, the initial dip of the pointer toward 'zero' is caused by _____________. A. good insulation B. the leakage of ... of dirty insulation C. the capacitance of the circuit D. the dielectric absorption effect of the insulation

Last Answer : Answer: C

When a megohmmeter is being used to test insulation resistance, current leakage along the surface of the insulation is indicated by the megohmmeter's pointer _____________. A. dipping toward zero then raising slowly B. continually rising as test voltage is applied C. kicking slightly down scale as voltage is applied D. fluctuating around a constant resistance reading

Description : When a megohmmeter is being used to test insulation resistance, current leakage along the surface of the insulation is indicated by the megohmmeter's pointer _____________. A. dipping toward ... kicking slightly down scale as voltage is applied D. fluctuating around a constant resistance reading

Last Answer : Answer: C

You are testing the insulation in an AC generator with a megohmeter. The resistance value of a dry, clean winding will ____________. A. continue to rise as the test potential is maintained, becoming fairly steady as the leakage current stabilizes B. remain constant as the temperature of the windings increases C. continue to drop as the potential is maintained, becoming fairly steady after 5 to 7 minutes D. stabilize after approximately 2 to 4 minutes of fluctuation

Description : You are testing the insulation in an AC generator with a megohmeter. The resistance value of a dry, clean winding will ____________. A. continue to rise as the test potential is maintained, ... fairly steady after 5 to 7 minutes D. stabilize after approximately 2 to 4 minutes of fluctuation

Last Answer : Answer: A

When a megohmmeter is used to test insulation, the gradual rise of the pointer reading as a result of continued cranking, is caused by _____________. A. good conductor resistance B. the leakage of current along the surface of dirty insulation C. the inductive reactance of the windings D. the dielectric-absorption effect of the insulation

Description : When a megohmmeter is used to test insulation, the gradual rise of the pointer reading as a result of continued cranking, is caused by _____________. A. good conductor resistance B. the ... insulation C. the inductive reactance of the windings D. the dielectric-absorption effect of the insulation

Last Answer : Answer: D

Heat transfer in the laminar sub-layer in case of a liquid flowing through a pipe, is mostly by (A) Eddies current (B) Conduction (C) Convection (D) None of these

Description : Heat transfer in the laminar sub-layer in case of a liquid flowing through a pipe, is mostly by (A) Eddies current (B) Conduction (C) Convection (D) None of these

Last Answer : (B) Conduction

Calculate the conduction density of a material with resistivity of 0.02 units and electric intensity of 12 units. a) 300 b) 600 c) 50 d) 120

Description : Calculate the conduction density of a material with resistivity of 0.02 units and electric intensity of 12 units. a) 300 b) 600 c) 50 d) 120

Last Answer : b) 600

A boundary of separation between two magnetic materials is identified by which factor? a) Change in the permeability b) Change in permittivity c) Change in magnetization d) Conduction

Description : A boundary of separation between two magnetic materials is identified by which factor? a) Change in the permeability b) Change in permittivity c) Change in magnetization d) Conduction

Last Answer : a) Change in the permeability

Calculate the frequency at which the conduction and displacement currents become equal with unity conductivity in a material of permittivity 2. a) 18 GHz b) 9 GHz c) 36 GHz d) 24 GHz

Description : Calculate the frequency at which the conduction and displacement currents become equal with unity conductivity in a material of permittivity 2. a) 18 GHz b) 9 GHz c) 36 GHz d) 24 GHz

Last Answer : b) 9 GHz

For conductors, the free electrons will exist at a) Valence band b) Middle of valence and conduction band c) Will not exist d) Conduction band

Description : For conductors, the free electrons will exist at a) Valence band b) Middle of valence and conduction band c) Will not exist d) Conduction band

Last Answer : d) Conduction band

Conduction in metals is due to a) Electrons only b) Electrons and holes c) Holes only d) Applied electric field

Description : Conduction in metals is due to a) Electrons only b) Electrons and holes c) Holes only d) Applied electric field

Last Answer : a) Electrons only

If deck machinery is expected to be idle for an extended period of time you should____________. A. have electrical safety gloves available in case of electrical shock before running B. perform a 'high pot' test to determine the condition of the insulation C. water wash the motor and controller to remove any salt that may interfere with smooth operation D. check run at regular intervals to inusre correct operation and to renew the internal coating of lubrication

Description : If deck machinery is expected to be idle for an extended period of time you should____________. A. have electrical safety gloves available in case of electrical shock before running B. perform ... run at regular intervals to inusre correct operation and to renew the internal coating of lubrication

Last Answer : Answer: D

Insulators have (A) A full valence band. (B) An empty conduction band. (C) A large energy gap. (D) All the above.

Description : Insulators have (A) A full valence band. (B) An empty conduction band. (C) A large energy gap. (D) All the above.

Last Answer : (C) A large energy gap.

A cable of core radius 1.25cm and impregnated paper insulation of thickness 2.13cm and relative permittivity 3.5. Compute the capacitance of the cable/km(in nF) a) 195.7 b) 179.5 c) 157.9 d) 197.5

Description : A cable of core radius 1.25cm and impregnated paper insulation of thickness 2.13cm and relative permittivity 3.5. Compute the capacitance of the cable/km(in nF) a) 195.7 b) 179.5 c) 157.9 d) 197.5

Last Answer : a) 195.7

The tubular and dorsal nervous system of chordates is related to the cephalization in these animals and to bilateral symmetry. The presence of neural integrating centers with concentration of neurons in the brains and the spinal cord (central nervous system, CNS) allowed the increase of the interaction complexity between these animals and the environment. Receptor (afferent conduction) and efferent (motor, regulatory and behavioral reactions) functions come out more sophisticated in chordates due to the presence of more well-developed neural networks. These features have been preserved by evolution as they provide adaptive advantage to their owners.

Description : The tubular and dorsal nervous system of chordates is related to the cephalization in these animals and to bilateral symmetry. The presence of neural integrating centers with concentration of ... These features have been preserved by evolution as they provide adaptive advantage to their owners.

Last Answer : How can the tubular-dorsal nervous system in chordates be compared to the nervous pattern present in invertebrates?

Air gap readings should be taken periodicly on electrical generation equipment to __________. A. determine the amount of varnish that can be applied to correct insulation problems B. determine the condition of the bearings C. provide for the correct proper tightening of the field coil bolts and correct lateral adjustment of the field coils D. increase machine efficiency

Description : Air gap readings should be taken periodicly on electrical generation equipment to __________. A. determine the amount of varnish that can be applied to correct insulation problems B. determine the ... field coil bolts and correct lateral adjustment of the field coils D. increase machine efficiency

Last Answer : Answer: B

Before testing insulation with a megohmmeter, the windings of large machines should be grounded for about 15 minutes just prior to the test as the ______________. A. insulation may be damaged B. insulation may be covered with moisture C. armature windings will have a greater number of leakage paths D. larger machines may acquire a charge of static electricity during operation

Description : Before testing insulation with a megohmmeter, the windings of large machines should be grounded for about 15 minutes just prior to the test as the ______________. A. insulation may be damaged ... number of leakage paths D. larger machines may acquire a charge of static electricity during operation

Last Answer : Answer: D

Before testing insulation with a megohmmeter, the windings of large machines should be grounded for about 15 minutes just prior to the test, because the ___________. A. static charge of the machine may give a false reading B. armature will have a greater number of leakage paths C. insulation may be damaged D. insulation may be covered with moisture

Description : Before testing insulation with a megohmmeter, the windings of large machines should be grounded for about 15 minutes just prior to the test, because the ___________. A. static charge of the machine ... number of leakage paths C. insulation may be damaged D. insulation may be covered with moisture

Last Answer : Answer: A

An electrical connection between the wiring of an electric motor and its metal frame is known as a/an _____________. A. eddy current B. ground C. impedance D. flux leakage

Description : An electrical connection between the wiring of an electric motor and its metal frame is known as a/an _____________. A. eddy current B. ground C. impedance D. flux leakage

Last Answer : Answer: B

Which form of heat transfer travels the fastest,convection or conduction?

Description : Which form of heat transfer travels the fastest,convection or conduction?

Last Answer : Conductor. A solid object is much better at conducting than gas, that’s why wires are wired. Air has a higher resitance to change, but also changes more than a static object, with different currents and influencing variables like humidity, barometric pressure etc.