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Answer : The D.C. motors preferred for traction applications beacuse the speed is inversely proportional to the torque and the torque is proportional to square of armature current.

Description : Why thyristor are not preferred for inverter?

Description : 9 leds each of 1 volt drop is series with 9  volt battery , do we need a resistor?(SMD leds) I have seen some smd leds without resistor !

Answer : We connect resistor to limit the current. So, it depends upon the current rating of the LED, which is provided by manufacturer.

Answer : Because it has a higher switching frequency and heat tolerance.

Description : Early astronomers thought that galaxies were single stars. Why was this mistake easy to make? A. Galaxies are so far away that they look like a single star. B. Galaxies are made of stars that you ... C. Light from galaxies collects into a single beam. D. Earth is small and galaxies are much larger.

Description : Why silicon is preferred over Ge?

Answer : 1) Silicon is plenty available compared to Ge. 2) Extraction process of Si is easy and less expensive. 3) Si has more thermal stability as compared to Ge. 4) Si has more breakdown voltage as compared to Ge.

Description : Why solar system is preferred now a days ? Justify your answer. 

Answer : Since availability of fossil fuels like coal are limited in future so there is more importance of solar power in the energy deficient because of following advantages of solar power Fuel is ... .  10. solar system technology are ideally suited to distributed applications ( Decentralized system)

Description : Why is pulse train gating preferred over pulse gating? Explain with relevant circuit and waveforms, the pulse train gating of SCRs.

Description : When two semiconductors of pand n-type are brought in contact, they form p-n junction which acts like a/an (1) Conductor (2) Oscillator (3) Rectifier (4) Amplifier

Answer : Rectifier

Description : Which of the following elements are used as dopants in silicon or germanium semiconductors? A) Antimony B) Phosphorus C) Arsenic D) All the above

Answer : Which of the following elements are used as dopants in silicon or germanium semiconductors? A) Antimony B) Phosphorus C) Arsenic D) All the above

Description : Find out number of data lines required to interface 16 LEDs arrange in the 4 x 4 matrix form.

Answer : 4+4=8, eight lines are required for 4x4 matrix of 16 LEDs

Description : In which material, valence electrons are tightly bounded to their parent atoms ? (a) Conductor (b) Semiconductor (c) Insulator (d) Magnetic 

Answer : Insulator  material

Description : The semiconductor used for LEDs emitting in the visible range is  (a) GaAs (b) GaAlAs (c) GalnAs (d) GaAsP

Answer : The semiconductor used for LEDs emitting in the visible range is GaAsP

Answer : The power consumption of LEDS may be of the order of 5 to 10 milli-amperes.

Answer : LEDs normally work on a voltage of 1 to 2 V.

Description : The dominant charge carriers in p-type semiconductors are: w) neutrons x) electrons y) protons z) holes

Answer : ANSWER: Z -- HOLES

Description : In N-type semiconductors the majority of the carriers are: w) holes x) electrons y) protons z) neutrons 

Answer : ANSWER: X -- ELECTRONS

Answer : In elections devices semi conducters are used 

Description : When making an entrance into a social gathering, do you make your presence known so everyone notices you, slip in and look for someone you know, or sneak in as quietly as possible and find a safe spot to hide? Why?

Description : Why do you support the five stage method of Herbart? Options: A) In this there is no scope for individual diversity of students. B) Under this, generalization is not required to be done while ... In this method, it is difficult to make co-ordination between various subjects. D) All of these

Answer : D) All of these 

Description : Why do teachers use teaching aid? Options: A) To make teaching fun-filled B) To teach within understanding level of students C) For students’ attention D) To make students attentive

Answer : B) To teach within understanding level of students 

Description : Why do teachers use teaching aid? (A) To make teaching fun-filled (B) To teach within understanding level of students (C) For students’ attention (D) To make students attentive

Answer : (B) To teach within understanding level of students

Description : Consider the following statements. Which of these statements are correct ?  (1) Reactance relays are preferred for ground fault relaying  (2) Impedance relays are most suitable for:protecting long transmission lines  (3) Mho relays are best ... (1) and (3) (C) (2) and (4) (D) (1), (2) and (4)

Answer : Consider the following statements. Which of these statements are correct ?  (1) Reactance relays are preferred for ground fault relaying  (2) Impedance relays are most suitable for:protecting long transmission lines  (3) Mho relays are ... (1) and (3) (C) (2) and (4) (D) (1), (2) and (4)

Answer : The conduction of electricity, in semiconductors, takes place due to movement of electrons and holes.

Description : Both donor and acceptor impurities are present in the combination of (a) Phosphorous - Arsenic (b) Aluminium - Antimony (c) Boron - Gallium (d) Arsenic - Antimony

Description : Three materials X, Y and Z having relative permittivity 2.5, 3.0 and 4.0 respectively are used in a single core cable. The materials on inner most and outer most layer respectively should be (a) X and Y (b) Y and Z (c) X and Z (d) Z and X 

Answer : Answer is option d Because the material with high relative permitivity should be used as the inner most layer of the cable,to withstand with the  high currents flowing in the conductor 

Description : Angles project true size only when the plane containing the angle and plane of projection are  (a) Aligned (b) Adjacent (c) Perpendicular (d) Parallel

Description : Strong and ductile materials (a) Polymers (b) Ceramics (c) Metals (d) Semiconductors

Answer : (c) Metals

Description : Classify the solids into conductors, semiconductors and insulators on the basis of band theory of solids. 

Answer : In conductors there is no energy gap between valance band and conduction band, they are overlapped on each other. So electrons can jump from valance band to conduction band easily and material ... band when some amount of energy is supplied to it. Therefore insulators cannot conduct the current.

Description : Name two good conductors, two good insulators, and two semiconductors.

Answer : In general all metals are good conductors, with silver the best and copper second.

Description : Why do transformers make noise?

Answer : Transformers make noise based on it out put if an transformer outputs is 400v maximum than a 398v be apply to that transformer it also make a noise because of that 

Description : While considering the seven leadership styles described by the leadership continuum, all of the following are variables that need to be considered for a manager, EXCEPT, (a) manager's preferred style ... style based on knowledge. (d) manager's preferred style based on confidence in upper management.

Answer : (d) manager's preferred style based on confidence in upper management. 

Description : In a transmission line if booster transformers are to be used, preferred location will be  (A) At the receiving end (B) At the sending end (C) At the intermediate point (D) Anywhere in the line 

Answer : In a transmission line if booster transformers are to be used, preferred location will be At the intermediate point

Description : Who are the creditors of a Corporation ? (1) Bond holders (2) Stock holders (3) Both Bond and Stock holders (4) Holders of preferred stock

Answer :  Both Bond and Stock holders 

Description : Ferrites are types of (a) magnetic material (b) conducting material (c) semiconducting material (d) insulating material

Answer : Ferrites  are  types  of  magnetic  material.

Description : A radioactive isotope has a half-life of 10 days. If today there are 125 g of it left, what was its original weight 40 days earlier  (a) 600 g (b) 1000 g (c) 1250 g (d) 2000 g 

Answer : Half life = 10days  The formula which is, 1/(2)^n × original weight = Weight left today.  To obtain the value of n = divide no of days by half life ie.,n= 40/10= 4 n=4 So, 1/(2)^n × original Weight = 125g 1/(2)^4 × Original weight = 125 Original weight = 16×125 = 2000g

Description : X-rays are used for the study of crystal structure because  (a) X-rays are completely absorbed by the crystal (b) the wavelength of X-ray is of the same order of magnitude in the inter ... in comparison with the inter-atomic spacing in crystals (d) the crystals are completely transparent to X-rays

Answer : the wavelength of X-ray is of the same order of magnitude in the inter atomic spacing in crystals 

Description : What are the basic laws of physics?

Description : What are the basics of physics?

Description : A material has conductivity of 10–2 mho/m and relative permittivity of 4. The frequency at which the conduction current in the medium is equal to the displacement current, is (a) 450 MHz (b) 900 MHz (c) 45 MHz (d) 90 MHz

Description : The following property of semiconductors cannot be determined from Hall effect: (1) Semiconductor is n–type or p–type (2) The carrier concentration (3) The mobility of semiconductor (4) The atomic concentration of semiconductor

Answer : The following property of semiconductors cannot be determined from Hall effect: The atomic concentration of semiconductor

Description : Photoconductivity is a characteristic of semiconductors. When light falls on certain semiconductors, it (a) Sets free electrons from some of the atoms, increasing the conductivity (b) Ejects ... Establishes a potential difference creating a source of EMF (d) Produces heat raising the temperature

Answer : Photoconductivity is a characteristic of semiconductors. When light falls on certain semiconductors, it Sets free electrons from some of the atoms, increasing the conductivity

Answer : An element used in semiconductors whose atoms have three valence electrons is An acceptor.

Answer : An acceptor is an element used in semiconductors whose atoms have three valence electrons.

Answer : The impurity atoms is semiconductors reduce the energy gap.

Answer : Intrensic purely made Extremsic with doping of trivaalent pr pentavalent

Answer : If a D.C. motor is to be selected for conveyors, Series motor would be preferred.

Description : The ................ model is preferred for software development when the requirements are not clear. (A) Rapid Application Development (B) Rational Unified Process (C) Evolutionary Model (D) WaterfallModel

Answer : (C) Evolutionary Model

Description :  DC motors are still preferred for use in: -  a) Electric excavators steel mills and cranes b) Lathes and machine tools c) Flour mills and jaw crushers d) Paper industry

Answer :  DC motors are still preferred for use in: - Electric excavators steel mills and cranes

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