The electrical conductivity of a __________ decreases with rise in temperature. (A) Metal/alloy (B) Semi-conductor (C) Dielectric (D) None of these

The electrical conductivity of a __________ decreases with rise in
temperature.
(A) Metal/alloy
(B) Semi-conductor
(C) Dielectric
(D) None of these
by

1 Answer

Answer :

(A) Metal/alloy
by

Related questions

With increase in temperature, the electrical conductivity of a __________ decreases. (A) Semi-conductor (B) Metal or alloy (C) Dielectric (D) None of these

Description : With increase in temperature, the electrical conductivity of a __________ decreases. (A) Semi-conductor (B) Metal or alloy (C) Dielectric (D) None of these

Last Answer : (A) Semi-conductor

Pick out the wrong statement. (A) Lead can creep under its own weight at room temperature (B) The electrical conductivity of gold is considerably reduced by alloying additions due to the decrease in electron movement (C) Recrystallisation temperature decreases with decrease in strain in a cold worked metal (D) With increase in temperature, the electrical conductivity of intrinsic semi-conductor will increase

Description : Pick out the wrong statement. (A) Lead can creep under its own weight at room temperature (B) The electrical conductivity of gold is considerably reduced by alloying additions due to ... metal (D) With increase in temperature, the electrical conductivity of intrinsic semi-conductor will increase

Last Answer : (C) Recrystallisation temperature decreases with decrease in strain in a cold worked metal

With increase in temperature, the electrical conductivity of semiconductors (A) Increases (B) Decreases (C) Remain constant (D) Either (A) or (B), depends on the type of semi-conductor

Description : With increase in temperature, the electrical conductivity of semiconductors (A) Increases (B) Decreases (C) Remain constant (D) Either (A) or (B), depends on the type of semi-conductor

Last Answer : Option A

. With increase in temperature, the electrical conductivity of semiconductors (A) Increases (B) Decreases (C) Remain constant (D) Either (A) or (B), depends on the type of semi-conductor

Description : . With increase in temperature, the electrical conductivity of semiconductors (A) Increases (B) Decreases (C) Remain constant (D) Either (A) or (B), depends on the type of semi-conductor

Last Answer : Option A

Why does the conductivity of a semi conductor change with the rise in temperature ?

Description : Why does the conductivity of a semi conductor change with the rise in temperature ?

Last Answer : When a semi conductor is heated more & more electrons get enough energy to jump across the forbidden energy gap from valence band to the conduction band, where they are free to conduct electricity. Thereby increasing the conductivity of a semi conductor.

A metallic alloy in general as compared to their pure metal components is (A) More corrosion resistant (B) Having higher melting point (C) Having lower hardness, reactivity and fusibility (D) Having lower electrical conductivity

Description : A metallic alloy in general as compared to their pure metal components is (A) More corrosion resistant (B) Having higher melting point (C) Having lower hardness, reactivity and fusibility (D) Having lower electrical conductivity

Last Answer : (A) More corrosion resistant

Conductivity of semi conductor is increased by: a) Decrease of temperature b) By keeping temperature constant c) Increase of temperature d) none of above

Description : Conductivity of semi conductor is increased by: a) Decrease of temperature b) By keeping temperature constant c) Increase of temperature d) none of above

Last Answer : d) none of above

Dielectric (A) Is an electrical insulating material (B) Of low resistivity is preferred (C) Should have high thermal conductivity (D) Need not defy the corrosive action of chemicals

Description : Dielectric (A) Is an electrical insulating material (B) Of low resistivity is preferred (C) Should have high thermal conductivity (D) Need not defy the corrosive action of chemicals

Last Answer : (A) Is an electrical insulating material

Compute the conductivity when the current density is 12 units and the electric field is 20 units. Also identify the nature of the material. a) 1.67, dielectric b) 1.67, conductor c) 0.6, dielectric d) 0.6, conductor

Description : Compute the conductivity when the current density is 12 units and the electric field is 20 units. Also identify the nature of the material. a) 1.67, dielectric b) 1.67, conductor c) 0.6, dielectric d) 0.6, conductor

Last Answer : c) 0.6, dielectric

For gases, the thermal conductivity increases with temperature rise. For liquids, with increase in concentration, its thermal conductivity generally (A) Decreases (B) Increases (C) Remains unchanged (D) Increases exponentially

Description : For gases, the thermal conductivity increases with temperature rise. For liquids, with increase in concentration, its thermal conductivity generally (A) Decreases (B) Increases (C) Remains unchanged (D) Increases exponentially

Last Answer : (A) Decreases

During electrical desalting of crude oil, the electrical conductivity of a mixture of crude oil and water (which ranges between 3 to 8% water) __________ with increase in the amount of water. (A) Decreases (B) Increases (C) Remains unchanged (D) Decreases linearly

Description : During electrical desalting of crude oil, the electrical conductivity of a mixture of crude oil and water (which ranges between 3 to 8% water) __________ with increase in the amount of water. (A) Decreases (B) Increases (C) Remains unchanged (D) Decreases linearly

Last Answer : (B) Increases

If electrical conductivity increases with the increase of temperature of a substance, then it is a: (1) Conductor (2) Semiconductor (3) Insulator (4) Carborator

Description : If electrical conductivity increases with the increase of temperature of a substance, then it is a: (1) Conductor (2) Semiconductor (3) Insulator (4) Carborator

Last Answer : (2) Semiconductor Explanation: A solid substance that has conductivity between that of an insulator and that of most metals, either due to the addition of an impurity or because of temperature effects

If electrical conductivity increases with the increase of temperature of a substance, then it is a (1) Conductor (2) Semiconductor (3) Insulator (4) Carborator

Description : If electrical conductivity increases with the increase of temperature of a substance, then it is a (1) Conductor (2) Semiconductor (3) Insulator (4) Carborator

Last Answer : (2) Semiconductor Explanation: A solid substance that has conductivity between that of an insulator and that of most metals, either due to the addition of an impurity or because of temperature effects.

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

The removal of paint from electrical equipment, such as generators, should be cautiously undertaken because ____________. A. the mechanical shock of paint removal lessens the dielectric strength of the insulation B. the paint dust is composed of abrasive and semi-conducting materials which impair insulation C. paint dust buildup has a tendency to cause corrosion D. phase windings frequently become isolated from each other due to dust interference at the terminals

Description : The removal of paint from electrical equipment, such as generators, should be cautiously undertaken because ____________. A. the mechanical shock of paint removal lessens the dielectric strength ... phase windings frequently become isolated from each other due to dust interference at the terminals

Last Answer : Answer: B

Materials which can store electrical energy are called (A) magnetic materials. (B) semi conductors. (C) dielectric materials. (D) super conductors.

Description : Materials which can store electrical energy are called (A) magnetic materials. (B) semi conductors. (C) dielectric materials. (D) super conductors.

Last Answer : (C) dielectric materials.

A 'dielectric' is a/an ________________. A. electrical insulator B. current flow C. good conductor D. semiconductor material

Description : A 'dielectric' is a/an ________________. A. electrical insulator B. current flow C. good conductor D. semiconductor material

Last Answer : Answer: A

Pressure Cooker cooks faster because (1) boiling point decreases with rise of pressure (2) it cooks the food at low pressure (3) higher temperature is attained for cooking (4) the material of the cooker is a good conductor

Description : Pressure Cooker cooks faster because (1) boiling point decreases with rise of pressure (2) it cooks the food at low pressure (3) higher temperature is attained for cooking (4) the material of the cooker is a good conductor

Last Answer : (3) higher temperature is attained for cooking Explanation: In pressure cooker boiling point of water increases due to high pressure.

Pressure Cooker cooks faster because (1) boiling point decreases with rise of pressure (2) it cooks the food at low pressure (3) higher temperature is attained for cooking (4) the material of the cooker is a good conductor

Description : Pressure Cooker cooks faster because (1) boiling point decreases with rise of pressure (2) it cooks the food at low pressure (3) higher temperature is attained for cooking (4) the material of the cooker is a good conductor

Last Answer : higher temperature is attained for cooking 

Thermal conductivity of a gas at low density, __________ with increase in temperature. (A) Decreases (B) Increases (C) Remains unchanged (D) May increase or decrease; depends on the gas

Description : Thermal conductivity of a gas at low density, __________ with increase in temperature. (A) Decreases (B) Increases (C) Remains unchanged (D) May increase or decrease; depends on the gas

Last Answer : (B) Increases

The property due to which the resistance of some metal or compound vanishes under certain conditions is (A) Semi conductivity. (B) Super conductivity. (C) Curie point. (D) Magnetostriction.

Description : The property due to which the resistance of some metal or compound vanishes under certain conditions is (A) Semi conductivity. (B) Super conductivity. (C) Curie point. (D) Magnetostriction.

Last Answer : (B) Super conductivity.

The temperature at which the magnetic property of iron disappears (i.e., it becomes non-magnetic) and its electrical conductivity & specific heat also changes, is called the 'Curie point', which is __________ °C. (A) 768 (B) 908 (C) 1400 (D) 1539

Description : The temperature at which the magnetic property of iron disappears (i.e., it becomes non-magnetic) and its electrical conductivity & specific heat also changes, is called the 'Curie point', which is __________ °C. (A) 768 (B) 908 (C) 1400 (D) 1539

Last Answer : Option A

Which of the following is form of semi conductor memory in which it is possible to change the contents of selected memory locations by applying suitable electrical signals? a. CAM b. ROM c. EPROM d. Abacus

Description : Which of the following is form of semi conductor memory in which it is possible to change the contents of selected memory locations by applying suitable electrical signals? a. CAM b. ROM c. EPROM d. Abacus

Last Answer : EPROM

Which of the following is form of semi conductor memory in which it is possible to change the contents of selected memory locations by applying suitable electrical signals? a. CAM b. ROM c. EPROM d. Abacus

Description : Which of the following is form of semi conductor memory in which it is possible to change the contents of selected memory locations by applying suitable electrical signals? a. CAM b. ROM c. EPROM d. Abacus

Last Answer : c. EPROM

Which of the following is form of semi conductor memory in which it is possible to change the contents of selected memory locations by applying suitable electrical signals? a. CAM b. ROM c. EPROM d. Abacus

Description : Which of the following is form of semi conductor memory in which it is possible to change the contents of selected memory locations by applying suitable electrical signals? a. CAM b. ROM c. EPROM d. Abacus

Last Answer : c. EPROM

Pick out the correct statement. (A) 1 kcal/hr.m.°C is equal to 1 BTU/hr. ft.°F (B) In steady state heat conduction, the only property of the substance which determines the temperature distribution, is the thermal conductivity (C) In unsteady state heat conduction, heat flows in the direction of temperature rise (D) In heat transfer by forced convection, Grashoff number is very important

Description : Pick out the correct statement. (A) 1 kcal/hr.m.°C is equal to 1 BTU/hr. ft.°F (B) In steady state heat conduction, the only property of the substance which determines the ... in the direction of temperature rise (D) In heat transfer by forced convection, Grashoff number is very important

Last Answer : (B) In steady state heat conduction, the only property of the substance which determines the temperature distribution, is the thermal conductivity

Thermal conductivities of most of the liquids __________ with rise in temperature.(A) Increases (B) Decreases (C) Remains unchanged (D) May increase or decrease; depends on the liquid

Description : Thermal conductivities of most of the liquids __________ with rise in temperature. (A) Increases (B) Decreases (C) Remains unchanged (D) May increase or decrease; depends on the liquid

Last Answer : (B) Decreases

For concentrating an aqueous solution of a material like anhydrous Na2SO4, whose solubility decreases with rise in temperature, the most suitable evaporator is a __________ evaporator. (A) High pressure (B) Vacuum (C) Backward feed (D) None of these

Description : For concentrating an aqueous solution of a material like anhydrous Na2SO4, whose solubility decreases with rise in temperature, the most suitable evaporator is a __________ evaporator. (A) High pressure (B) Vacuum (C) Backward feed (D) None of these

Last Answer : (B) Vacuum

Viscosity of a liquid decreases __________ with rise in temperature. (A) Exponentially (B) Linearly(C) Logarithmically(D) None of these

Description : Viscosity of a liquid decreases __________ with rise in temperature. (A) Exponentially (B) Linearly (C) Logarithmically (D) None of these

Last Answer : (C) Logarithmically

Nickel is a __________ material. (A) Ferromagnetic (B) Semi-conductor (C) Paramagnetic (D) Ferroelectric

Description : Nickel is a __________ material. (A) Ferromagnetic (B) Semi-conductor (C) Paramagnetic (D) Ferroelectric

Last Answer : (A) Ferromagnetic

A semi-conductor is damaged & behaves like a conductor, on passing a strong electric current through it, because it heats up the crystals & breaks the covalent bonds resulting in __________ electrons. (A) Lack of free (B) Excess of (C) Decrease in (D) None of these

Description : A semi-conductor is damaged & behaves like a conductor, on passing a strong electric current through it, because it heats up the crystals & breaks the covalent bonds resulting in __________ electrons. (A) Lack of free (B) Excess of (C) Decrease in (D) None of these

Last Answer : (B) Excess of

Indicate the three types oftransmissionline energylosses. a. I2R, R , and temperature b. Radiation, I2R, and dielectric heating c. Dielectric separation, insulation breakdown, and radiation d. Conductor heating, dielectric heating, and radiation resistance.

Description : Indicate the three types oftransmissionline energylosses. a. I2R, R , and temperature b. Radiation, I2R, and dielectric heating c. Dielectric separation, insulation breakdown, and radiation d. Conductor heating, dielectric heating, and radiation resistance.

Last Answer : b. Radiation, I2R, and dielectric heating

Due to which of the following reasons the cables should not be operated too hot ? (a) The oil may loose its viscosity and it may start drawing off from higher levels (b) Expansion of the oil may cause the sheath to burst (c) Unequal expansion may create voids in the insulation which will lead to ionization (d) The thermal instability may rise due to the rapid increase of dielectric losses with temperature (e) All of the above

Description : Due to which of the following reasons the cables should not be operated too hot ? (a) The oil may loose its viscosity and it may start drawing off from higher levels (b) Expansion of the ... instability may rise due to the rapid increase of dielectric losses with temperature (e) All of the above

Last Answer : (e) All of the above

Which of the following criterion is used for any metal to be used as a cooking material? (1) More specific heat (2) More thermal conductivity (3) Less thermal conductivity (4) Less electrical conductivity

Description : Which of the following criterion is used for any metal to be used as a cooking material? (1) More specific heat (2) More thermal conductivity (3) Less thermal conductivity (4) Less electrical conductivity

Last Answer : (3) Less thermal conductivity Explanation: A metal to be used as a cooking material should have less thermal conductivity.

The metal whose electrical conductivity is more, is – (1) copper (2) aluminium (3) silver (4) lead

Description : The metal whose electrical conductivity is more, is – (1) copper (2) aluminium (3) silver (4) lead

Last Answer : (3) silver Explanation: Copper ; 9% less conductive than silver: aluminium is 1 0% less conductive than copper; while steel is the least conductive among the given options. The most electrically conductive metal is silver.

Which of the following metal has maximum electrical conductivity?

Description : Which of the following metal has maximum electrical conductivity?

Last Answer : Silver

Which of the following criterion is used for any metal to be used as a cooking material ? (1) More specific heat (2) More thermal conductivity (3) Less thermal conductivity (4) Less electrical conductivity

Description : Which of the following criterion is used for any metal to be used as a cooking material ? (1) More specific heat (2) More thermal conductivity (3) Less thermal conductivity (4) Less electrical conductivity

Last Answer : Less thermal conductivity 

The metal whose electrical conductivity is more, is (1) copper (2) aluminium (3) silver (4) lead

Description : The metal whose electrical conductivity is more, is (1) copper (2) aluminium (3) silver (4) lead

Last Answer : silver

Coke oven regenerators are made of __________ bricks. (A) Fire clay (B) Silica (C) Low thermal conductivity (D) High electrical conductivity

Description : Coke oven regenerators are made of __________ bricks. (A) Fire clay (B) Silica (C) Low thermal conductivity (D) High electrical conductivity

Last Answer : (A) Fire clay

Presence of even very minute amount (say 0.1%) of __________ in copper, reduces its electrical conductivity very seriously. (A) Bismuth (B) Arsenic (C) Antimony (D) Both (B) and (C)

Description : Presence of even very minute amount (say 0.1%) of __________ in copper, reduces its electrical conductivity very seriously. (A) Bismuth (B) Arsenic (C) Antimony (D) Both (B) and (C)

Last Answer : (D) Both (B) and (C)

Psychrometry deals with the properties of gas-vapor mixture. Humidity can be determined by the measurement of the __________ of a fibre. (A) Electrical resistance (B) Thermal conductivity (C) Strength (D) None of these

Description : Psychrometry deals with the properties of gas-vapor mixture. Humidity can be determined by the measurement of the __________ of a fibre. (A) Electrical resistance (B) Thermal conductivity (C) Strength (D) None of these

Last Answer : (A) Electrical resistance

Velocity of liquid hydrocarbon fuels in a pipeline cannot be measured by magnetic flow-meters, because their __________ is very low/small. (A) Thermal conductivity (B) Electrical conductivity (C) Specific gravity

Description : Velocity of liquid hydrocarbon fuels in a pipeline cannot be measured by magnetic flow-meters, because their __________ is very low/small. (A) Thermal conductivity (B) Electrical conductivity (C) Specific gravity

Last Answer : (C) Specific gravity

For a perfect dielectric, which parameter will be zero? a) Conductivity b) Frequency c) Permittivity d) Permeability

Description : For a perfect dielectric, which parameter will be zero? a) Conductivity b) Frequency c) Permittivity d) Permeability

Last Answer : a) Conductivity

With increase in temperature, the rate of leaching increases, because the (A) Diffusivity of solute increases (B) Viscosity of solvent decreases (C) Thermal conductivity of solute increases (D) None of these

Description : With increase in temperature, the rate of leaching increases, because the (A) Diffusivity of solute increases (B) Viscosity of solvent decreases (C) Thermal conductivity of solute increases (D) None of these

Last Answer : (A) Diffusivity of solute increases

With increase in temperature, the thermal conductivity of steel (A) Increases (B) Decreases (C) Remains unchanged (D) Increases exponentially

Description : With increase in temperature, the thermal conductivity of steel (A) Increases (B) Decreases (C) Remains unchanged (D) Increases exponentially

Last Answer : (B) Decreases

With increase in temperature, the thermal conductivity of non-metallic amorphous solids (A) Decreases (B) Increases (C) Remain constant (D) First decreases upto certain temperature and then increases

Description : With increase in temperature, the thermal conductivity of non-metallic amorphous solids (A) Decreases (B) Increases (C) Remain constant (D) First decreases upto certain temperature and then increases

Last Answer : (B) Increases

With increase in temperature, the thermal conductivity of fresh lubricating oil (A) Increases (B) Decreases (C) Remains unchanged (D) May increase or decrease; depends on its composition

Description : With increase in temperature, the thermal conductivity of fresh lubricating oil (A) Increases (B) Decreases (C) Remains unchanged (D) May increase or decrease; depends on its composition

Last Answer : (B) Decreases

With increase in temperature, the thermal conductivity of most liquids (A) Increases (B) Decreases (C) Remain same (D) First increases upto a certain temperature and then becomes constant

Description : With increase in temperature, the thermal conductivity of most liquids (A) Increases (B) Decreases (C) Remain same (D) First increases upto a certain temperature and then becomes constant

Last Answer : (C) Remain same

With increase in temperature, the thermal conductivity of a gas (A) Increases (B) Decreases (C) Remain same (D) May increase or decrease depending on the type of gas

Description : With increase in temperature, the thermal conductivity of a gas (A) Increases (B) Decreases (C) Remain same (D) May increase or decrease depending on the type of gas

Last Answer : (A) Increases