Recent questions tagged electric

Description : Compressor wizards, share your wisdom?

Last Answer : There is this chap that bought a small compressor for electronics dusting purposes and compared it to a normal blower style duster. The compressor was a complete failure.

Description : How would you handle UPS packages with this setup?

Last Answer : Pick them up from the depot…

Description : Q-12 which Testing is used in high thickness job in LNT?

Last Answer : Ultrasonic Testing.

Description : Q-11 What is the purpose of dust free zone in LNT?

Last Answer : Special dust-free enclosures with temperature and humidity control enable the Company to achieve manufacturing excellence in Class 1 nuclear island components. L&T manufactures reactor vessels, steam ... and Heat Exchangers are manufactured within dust-free enclosures at L&T's workshops.

Description : Q-10 In TANDEM SAW process, why AC and DC both currents are used?

Last Answer : AC will melt the base metal and make weld pool in the base metal and by DC it will fill the weld metal in the weld pool.

Description : Q-9 how many electrodes are used in the TANDEM SAW? What is the polarity of the both electrode?

Last Answer : In TANDEM SAW process there are more than one electrode is used. But for first electrode alternative current and for second electrode direct current shall be used.

Description : Q-8 which types of SAW process are used in Larsen and Toubro?

Last Answer : Tandem SAW Narrow groove application As the section thickness of vessel for nuclear and petroleum industry increase, the desire for reduced weld time and material consumption has driven the joint on ... process is carried out. LNT practice that for many of high thickness nuclear pressure vessel.

Description : Q-7 during welding process, why sinusoidal wave form is converted in to the square wave form?

Last Answer : In sinusoidal wave, we get maximum energy at one point only. So for the more amount of maximum energy we can get by converting the sinusoidal wave form in to the square wave form, and more penetration and deposition rate is achieved due to maximum energy.

Description : Q-6 which innovative welding technique is used by L & T in T joint welding?

Last Answer : In T joint welding backing is required in other side while welding on one side. Flux goes on another side from the root opening and that has to be removed before welding other side. During the ... of the job is also not required by other sources since one side of welding serve the purpose.

Description : Q-5 what is the phenomena behind the overhead welding?

Last Answer : In overhead welding during welding flux has more fluidity and comes on the surface when the metal is deposited in the root gape. There are different freezing point metal and the flux. so metal have low ... deposit in the root gape and flux have a high freezing point so its deposit on the metal .

Description : Q -4 what is the purpose of sodium, silicon and potassium in core element?

Last Answer : • Silicon - deoxidize & form slag • Sodium - stabilize arc & form slag • Potassium - stabilizes the arc & form slag

Description : Q-3 Write the energy distribution for different polarity?

Last Answer : DCEP – 67% at electrode and 33% at job. • DCEN – 33 % at electrode and 67% at job. • AC – 50 % at electrode and 50% job.

Description : Q-2 what are the functions of electrode covering in SMAW process?

Last Answer : To facilitate arc ignition and give arc stability. To generate gas for shielding the arc & molten metal from air contamination. To de-oxidise the weld metal and flux impurities into the slag. To ... to support the molten weld metal). To control hydrogen contents in the weld. (basic type)

Description : Q-1 what is the function of copper coating in SAW filler wire?

Last Answer : to assure a good electric contact between wire and contact tip • to assure a smooth feed of the wire through the guide tube, feed rolls and contact tip (decrease contact tube wear) • to provide protection against corrosion

Description : at the terminal of a three-phase 6.6Kv alternator a load R=200 ohm is connected between two-phase and the third phase is opened. Z1=z2=5 ohm Zo=2 find out the fault current .

Last Answer : 32A

Description : The emission of number of photo electrons depends upon a) The colour of the body b) The frequency of incident light c) The intensity of light d) All of the above

Last Answer : c) The intensity of light

Description : Black body radiations depends upon a) The shape and nature of the body b) The velocity of radiations and colour of the body c) The temperature of the body d) All of the above

Last Answer : c) The temperature of the body

Description : The output of two inputs OR gate is zero only when: (a) Both are one (b) Both are zero (c) Either input is 1 (d) None

Last Answer : (b) Both are zero

Description : Photo diode operates in the _______ condition (a) Forward bias (b) null (c) both a & d (d) reverse bias

Last Answer : (d) reverse bias

Description : In the N-type semiconductor the charge carries are a) Holes b) Neutrons c) Protons d) Electrons

Last Answer : d) Electrons

Description : In a P-type semiconductor the charge carriers are a) Electrons b) Holes c) Protons d) Neutrons

Last Answer : b) Holes

Description : A combination of N-type and P-type material is called a) Diode b) Transistor c) Resistor d) Capacitor

Last Answer : a) Diode

Description : The maximum stress that a body can tolerate is called: a) UTS b) Permanent stress c) Elastic strength d) Plastic stress

Last Answer : a) UTS

Description : When stress is increased beyond elastic limit and material is permanently changed this property is a) Permanent stress b) Elasticity c) Yield strength d) Plasticity

Last Answer : d) Plasticity

Description : The ratio of stress to volumetric strain is called a) Shear Modulus b) Young’s Modulus c) Bulk Modulus d) Modulus of elasticity

Last Answer : c) Bulk Modulus

Description : The ratio of shear stress to shear strain is a) Shear modulus b)Young’s Modulus c) Bulk Modulus d)None of above

Last Answer : b)Young’s Modulus

Description : The ratio of stress to strain i: a) Modulus of conductivity b) Modules of Elasticity c) Modulus of electricity d) Modulus of Viscosity

Last Answer : b) Modules of Elasticity

Description : The deformation of a solid when stress is applied is called a) Strain b) Elasticity c) Rigidity d) Pressure

Last Answer : a) Strain

Description : The ability of a body to return to its original shape is called: a) Plasticity b) Elasticity c) Strain d) Stress

Last Answer : b) Elasticity

Description : Which class of material would you classify Nylon a) Fibres b) Polymer c) Ceramics d) Glass

Last Answer : b) Polymer

Description : The work is stored in an inductor in form of.......: a. Elastic potential energy b. Kinetic energy c. Potential energy d. Gravitational potential energy

Last Answer : b. Kinetic energy

Description : Sensitivity of a galvanometer can be increased by a) Increasing the number of turns of the coil b) Decreasing the magnetic field c) Increasing the ratio c ⁄BAN d) Decreasing the area of the coil

Last Answer : a) Increasing the number of turns of the coil

Description : Electrical energy is measured in a. watt b. horse power c. kilo watt d. kilowatt hour

Last Answer : d. kilowatt hour

Description : Reciprocal of resistivity is called a. Resistance b. Inductance c. Conductivity d. Flexibility

Last Answer : c. Conductivity

Description : Resistance of a super conductor is a. Finite b. Infinite c. Zero d. changes with every conductor

Last Answer : c. Zero

Description : How much heat does a 40 W bulb generates in one hour? a. 144000J b. 144J c. 1.44J d. 14J

Last Answer : a. 144000J

Description : One kilowatt hour is the amount of energy delivered during a. one second b. one day c. one minute d. one hour

Last Answer : b. one day

Description : When same current passes for same time through a th ick and thin wire a. more heat is produced in thick wire b. more heat is produced in thin wire c. no heat is produced in wire d. less heat is produced in thick wire

Last Answer : More heat is produced in thin wire. Reason:The resistance of a thin wire is greater than the resistance of a thick wire because a thin wire has fewer electrons to carry the current. And higher resistance produces more heat therefore thin wire overheats.

Description : Resistance of a conductor depends upon a. nature of conductor b. dimension of conductor c. physical state of the conductor d. all of above

Last Answer : d. all of above

Description : The current through a metallic conductor is due to the motion of a. free electrons b. Protons c. Neutrons d. still under controversy

Last Answer : a. free electrons

Description : Selenium is: (a) Conductor (b) Insulator in the dark are becomes conductor when exposed to light (c) An insulator (d) None of these

Last Answer : (b) Insulator in the dark are becomes conductor when exposed to light

Description : An example of photoconductor is: (a) Iron (b) Aluminum (c) Carbon (d) Selenium

Last Answer : (d) Selenium

Description : Explain about Electric Energy Conservation? How Energy conservation can be done in Lighting?

Last Answer : Ans: Today in India, the per capita availability of energy is much less than the energy in developed countries. The demand for energy is always out placing availability, the shortfall being ... In streets of rural areas and side streets, street lighting luminaires with fluorescent lamps are used.

Description : Electric Cement Mixers

Last Answer : Hand mixing is always imperfect, laborious and slow. Using this method, it is impossible to secure the thorough stirring and kneading action that a good mixing machine gives. If a machine ... material's liquid state, through electronically controlled agitation or turning of the drum until delivery.

Description : Electric Bicycles

Last Answer : For most people, riding a bicycle is a very physical activity. If you're the type who doesn't like the idea of coming to school or work all sweaty and tired, you might have never considered ... allows them to move in the traffic and even in narrow lanes, making them more productive and efficient.

Description : Electric Brake

Last Answer : An electric brake is a device that uses electrically actuated components to stop or slow the motion of shafts. This type of brake is very useful in applications that require precise tension ... sprocket, gear or pullet. Usually, these electric brakes are designed to accept various drive components.

Description : How to Build an Electric Eye

Last Answer : How to Build an Electric Eye Experimenting with electricity has always been a delight for many people. With the building of an electric eye, it will not only be exciting but it can be used for various ... slide is closed. A rheostat can be used to control the flow of current as you want it.

Description : How to Build an Electric Car

Last Answer : How to Build an Electric Car Electric cars are a great way for us to enjoy speed and the thrills of racing cars on a small scale. Most kids grow up with a variety of electric radio ... hobby shop; you can always find good information and other enthusiasts that are interested in electric model cars.

Description : How to Lower Your Electric Bill ?

Last Answer : How to Lower Your Electric Bill The electric bill captures a huge brunt of your monthly expenses. It contains the accumulated cost of using every electrical device. Lowering the electric bill is clearly ... . Use each of them to your full advantage, preserving your monthly budget in the process.

Description : Electric Sprayer

Last Answer : With technology coming in leaps and bounds since the past century, it is just a matter of time before your average garden and home sprayers evolve too. The evolution comes in the form of the electric ... long as you're okay with the disadvantages it has, then you should be fine with getting it.