Electrical conductivities of semi-conductors are of the order of
__________ ohm/cm.
(A) 10-3
(B) 103
(C) 10-15
(D) 1015

1 Answer

Answer :

OptionA

Related questions

Description : . The inner wall of a furnace is at a temperature of 700°C. The composite wall is made of two substances, 10 and 20 cm thick with thermal conductivities of 0.05 and 0.1 W.m-1.°C-1 respectively. The ambient air is at 30°C ... from the outer surface in W.m-2 is (A) 165.4 (B) 167.5 (C) 172.5 (D) 175

Last Answer : (A) 165.4

Description : Materials having resistivity ranging from 1 to 100 ohm. cm is termed as (A) Conductor (B) Insulator (C) Semi-conductor (D) None of these

Last Answer : (C) Semi-conductor

Description : Electrostatic separation of minerals from each other is based on their differences in the following property. (A) Densities (B) Magnetic permeabilities (C) Electrical conductivities (D) Hardness

Last Answer : (C) Electrical conductivities

Description : Certain substances loose their electrical resistance completely at super low temperature. Such, substances are called. (1) Super conductors (2) Semi conductors (3) Dielectrics (4) Perfect conductors

Last Answer : (1) Super conductors Explanation: Superconductors are materials that carry electrical current with little or no resistance when cooled, below a certain temperature. While conventional superconductors need to ... temperature superconductors do so above the boiling point of liquid nitrogen (-196 °C).

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.

Description : Certain substances loose their electrical resistance completely at super low temperature. Such substances are called. (1) Super conductors (2) Semi conductors (3) Dielectrics (4) Perfect conductors

Last Answer : Super conductors

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

Description : __________ is a donor impurity for semi-conductors. (A) Boron (B) Antimony (C) Gallium (D) None of these

Last Answer : (B) Antimony

Description : On selling 25 balls at Rs. 1015, there is a profit equal to the cost price of 10 balls. What is the cost price of a ball? a) Rs. 31 b) Rs. 29 c) Rs. 35 d) Rs. 27 e) Rs. 39

Last Answer : b Profit = (S.P of 25 balls) - (C.P of 25 balls) = 1015 - (C.P of 25 balls) Given that Profit = (C.P of 10 balls) => 1015 - (C.P of 25 balls) = (C.P of 10 balls) => (C.P of 25 balls) + (C.P of 10 balls) = 1015 => C.P of 35 balls = 1015 => C.P of 1 ball=1015 / 35 = Rs. 29

Description : At constant temperature, the thermal conductivities of gases__________ with rise in pressure. (A) Decrease (B) Increase (C) Remain unchanged (D) May increase or decrease; depends on the pressure

Last Answer : (A) Decrease

Description : A steam pipe is intended to be insulated with two layers of insulating materials of different thermal conductivities. For minimum heat transfer to take place (A) The better insulation material should be put just ... to which insulating material is to be put inside (i.e., just next to the pipe)

Last Answer : (A) The better insulation material should be put just next to pipe (i.e., inside)

Description : India receives amount of solar energy each year a. 5×1010 kWh/year. c) 5×1015 kWh/year b. 4×1015 kWh/year. d) 5×1010 kWh/year

Last Answer : 5×1015 kWh/year

Description : The laser frequency when the light has the wavelength 800 nm is ∙ a. 375 x 1012 Hz ∙ b. 475 x 1015 Hz ∙ c. 375 x 109 Hz ∙ d. 375 x 1018 Hz

Last Answer : d. 375 x 1018 Hz

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

Last Answer : (A) Metal/alloy

Description : During coal carbonisation process, the conversion of semi-coke to coke is accompanied by an increase in the __________ of the mass. (A) Density (B) Porosity (C) Electrical resistivity (D) None of these

Last Answer : (A) Density

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

Description : What is the typical separation between the two conductors in a parallel wire line? A. 0.001 to 0.01 m B. 200 to 500 mm C. 0.635 to 15.24 cm D. 2.5 to 5 in.

Last Answer : C. 0.635 to 15.24 cm

Description : Which of the following have the highest thermal conductivities?  a. liquids  b. gases  c. metals  d. solids other than metals

Last Answer : metals

Description : If intensity of rainfall in cm per hour is I, percentage coefficient of run-off is P, area of catchment in  square kilometres is A, the total run-off Q, is given by  (A) Q = 1.758 102   API (B) Q = 2.758 ... API (C) Q = 2.758 103   API (D) Q = 2.758 103   A/PI

Last Answer : (C) Q = 2.758 × 103  × API

Description : a) Semi-conductors b) Pesticides c) Laser.

Last Answer : a) Semi-conductors: Semiconductor, solid or liquid material, able to conduct electricity at room temperature more readily than an insulator, but less easily than a metal. Such metals as copper, ... the infrared through the X-ray range. Masers are similar devices that produce and amplify microwaves.

Description : Give one example of doping which produces p-type of semi-conductors.

Last Answer : Ge doped with Al.

Description : The substances which have a large number of free electrons and offer a low resistance are called (a) insulators (b) inductors (c) semi-conductors (d) conductors

Last Answer : (d) conductors

Description : Semi-conductors have ________ temperature coefficient of resistance. (A) Negative (B) Positive (C) Both positive and negative (D) None of the above

Last Answer : (A) Negative

Description : Permanent magnets are made of (A) soft magnetic materials. (B) hard magnetic materials. (C) semi conductors. (D) super conductors.

Last Answer : (B) hard magnetic materials.

Description :  In case of semi-conductors, the ratio of conduction current to displacement current is: A) more than 200 and less than 1000 B) less than 100 but greater than 1/100 C) less than 1/100 D) more than 1000

Last Answer : In case of semi-conductors, the ratio of conduction current to displacement current is:  less than 100 but greater than 1/100

Description : With rise in temperature the resistance of semi-conductors?

Last Answer : With rise in temperature the resistance of semi-conductors decreases.

Description : Purity of oxygen used for blowing in steel making L.D. converter is 99.5%. The boiling point of oxygen is about __________ °C. (A) -53 (B) -103 (C) -183 (D) -196

Last Answer : (C) -183

Description : A potentiometer having the potential gradient of `2 mV//cm` is used to measure the difference of potential across a resistance of `10 ohm`. If a lengt

Last Answer : A potentiometer having the potential gradient of `2 mV//cm` is used to measure the difference of potential across a ... `) A. 1 B. 2 C. 5 D. 10

Description : A potentiometer having the potential gradient of `2 mV//cm` is used to measure the difference of potential across a resistance of `10 ohm`. If a lengt

Last Answer : A potentiometer having the potential gradient of `2 mV//cm` is used to measure the difference of potential across a ... `) A. 1 B. 2 C. 5 D. 10

Description : Ceramic materials (A) Are exemplified by clay and mica (B) Are poor electrical conductors due to lack of free electrons (C) Never exhibit polymorphism (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

Description : The power of a locomotive is 315 kW and the total weight of the train is 2000 kN. If the track resistance is 15 N per kN, the maximum speed that the locomotive can attain on level track will be a.43 kmph b.83 kmph c.103 kmph d.107 dynes e.38 kmph

Last Answer : e. 38 kmph

Description : Molecular volume of any perfect gas at 600 x 103 N/m2 and 27°C will be  (a) 4.17m3/kgmol  (b) 400 m3/kg mol  (c) 0.15 m3/kg mol  (d) 41.7 m3/kg mol  (e) 417m3/kgmol.

Last Answer : Answer : a

Description : What is the moment of inertia acting on a rectangle of width 15 mm and depth 40 mm about base by using theorem of parallel axes? a. 320 x 103 mm4 b. 300 x 103 mm4 c. 240 x 103 mm4 d. 80 x 103 mm

Last Answer : a. 320 x 103 mm4

Description : What three related electrical factors did George Ohm investigate?

Last Answer : the answer is current, voltage, and resistance

Description : How can Ohm law be used to calculate the electrical resistance of a piece of wire?

Last Answer : Ohm's law establishes the relationship between the current flowing in a conductor (represented by I), the potential difference across the two ends of the conductor (represented by P), and the resistance offered ... all materials. This is not true, as it only applies to 'linear' or 'ohmic' materials.

Description : What is unit of Electrical Capacity? (1) henry (2) farad (3) volt (4) ohm

Last Answer : (2) farad Explanation: Henry is unit of Magnetic Induction, volt is unit of Potential Difference, ohm is unit of Electric Resistance.

Description : The unit of electrical resistance is the _____________. A. ampere B. volt C. watt D. ohm

Last Answer : Answer: D

Description : why reactive ohm cannot converted electrical energy into heat?

Last Answer : Because it describes the resistance of element that store energy rather than dissipate energy as heat

Description : A cube of material of side 1 cm has a resistance of 0.002 ohm between its opposite faces. If the same volume of the material has a length of 8 cm and a uniform cross-section, the resistance of this length will be 

Last Answer : A cube of material of side 1 cm has a resistance of 0.002 ohm between its opposite faces. If the same volume of the material has a length of 8 cm and a uniform cross-section, the resistance of this length will be 0.128 ohm.

Last Answer : A wire of 0.14 mm diameter and specific resistance 9.6 micro-ohm-cm is 440 cm long. The resistance of the wire will be 27.4 ohm.

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

Description : Larger length & diameter water pipes are made by (A) Electrical resistance welding (B) Die casting (C) Semi-centrifugal casting (D) Continuous casting

Last Answer : options A

Description : Larger length & diameter water pipes are made by (A) Electrical resistance welding (B) Die casting (C) Semi-centrifugal casting (D) Continuous casting

Last Answer : Option C

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

Description : Why do acids and bases make good electrical conductors when dissolved in water?

Last Answer : Acids, bases, and salts are ionically bonded and easily separate into oppositely charged free ions in water solution. Both the positive and negative ions then act as charge carriers, moving in response to an applied electric field thus facilitating electrical conductivity.

Description : Why are metal electrical conductors?

Last Answer : atoms in a metal form a matrix wherein their outer electrons move freely

Description : Different components of the motherboard of a PC unit are linked together by sets of parallel electrical conducting lines. What are these lines called? A) Conductors B) Buses C) Connectors D) Consecutives

Last Answer : Answer : B

Description : To minimize magnetic field interaction between electrical conductors in physical proximity, it is best to keep them ___________________. A. parallel and as close as possible to each other B. at right angles ... practicable from each other D. at right angles and as far as practicable from each other

Last Answer : Answer: D

Description : A common type of protective covering used on electrical conductors is _____________. A. plain paper B. fibrous braid C. silver sheathing D. babbitt sheathing

Last Answer : Answer: B

Description : Different components on the motherboard of a PC processor unit are linked together by sets or parallel electrical conducting lines. What are these lines called? a. Conductors b. Buses c. Connectors d. Connectively

Last Answer : Buses