Once the gas ionizes, the operation of the lamp can be maintained at a lower voltage, and the maintaining voltage may vary between 10-20 volts depending on the lamp and operating current. neon glow discharge lamps) are widely used gas discharge lamps for indicating the “on” state of electric installations. This effect is noticed when objects are lit by gas-discharge lamps. However, if the device’s output voltage can be measured without drawing current, then output voltage will equal emf (even for a very depleted battery). How do line voltage excursions affect HID and fluorescent ballast regulation and lamp operation? But what about line voltage excursions? Which of the following statement is true? More advanced gas-discharge tubes have been made with control elements so that their “turn-on” voltage could be adjusted by an external signal. | Stroboscopic effect is the phenomenon which makes moving objects like fan blades to appear to be standstill, and a wave of the hand to appear as if it occurred in a series of jumps. This is because the electrodes gap in the neon bulb of starter is much lesser than that of the fluorescent lamp. ... the gas discharge is more constant than with conventional ballasts which interrupt the lamp current At that full voltage first the glow discharge is established in the starter. Select the application of fluid coupling fitting from the following: a) acts as a voltage limiter b) enables no-load start-up of prime-mover c) works on the principle of eddy current d) none of the above Then it initiates and maintains the xenon arc. Corona Mcq’s Interview Questions. So this lamp was used in movie projectors, searchlights, etc. Absorption Instrumentation Questions & Answers 1. It is not possible to apply the line voltage directly to such lamp, be it AC or DC, a higher or a lower magnitude. Answer: 1 and 3. Multiple Choice Questions of Electric Illumination 1. In normal conditions, the human eye does not notice the fact. Physics is a branch of science which studies the properties of matter, energy and their mutual relationship. Glow lamps (e.g. a) The saturation voltage V CF of silicon transistor is more than germanium transistor. All fluorescent lamps are essentially high vacuum lamps, filled to a very low pressure with one or more inert gases. Xenon Discharge Lamp :-It possessed two tungsten electrod separated by some distance. What is Stroboscopic Effect? a) Filter b) Reflector c) Converging lens d) Detector Answer: d Explanation: To measure the amount of radiation absorbed and transmitted detector is very important. Nowadays, the most widely used lamps are gas discharge lamps. As we know, Vs/Vp = Ns/Np. a) to ignite the lamp b) to stabilize the gas discharge c) to reduce lumen output of the lamp d) to supply power to the lamp 14. The state of the gas discharge lamp is monitored. c) The saturation voltage V CE for silicon transistor is same as that for germanium. b) The saturation voltage V CE for germanium transistor is more than silicon transistor. The noble gas enables the arc's initial strike. A method and apparatus for operating at least one gas discharge lamp includes supplying a gas discharge lamp with high-frequency alternating voltage from an externally controlled lamp generator having an operating frequency being variable for dimming the gas discharge lamp. More advanced gas-discharge tubes have been made with control elements so that their “turn-on” voltage could be adjusted by an external signal. The fundamental equation for the kinetic theory of gas is derived with the following Transformer MCQ (Multiple Choice Questions) with blog, what is quora, what is ... Primary voltage (Vp) = 220 Volt. Are the effects different for the two lamp/ballast systems?Sure, manufacturers design their arc discharge lamps to perform best when operated on a line voltage within the range of ballast design (indicated on the ballast nameplate). Generally a typical pulse has a peak voltage of 2500V and it has durability for only 1 microsecond only. Unfortunately, that's a common attitude of those holding the corporate purse strings. This tube is filled with noble gas and often also contains suitable metal or metal salts. Which is the missing block in the block diagram for Absorption of Radiation Instrument given below? This is a good source of continuous plus additional intense radiation. Shown below is a 'typical' current vs. voltage characteristic for a gas discharge tube. Nowadays, because of heavy fluctuation of voltage, the lives of bulbs are being reduced. 440/220 = Ns/Np. Discharge Lamp: HIGH VOLTAGE ENGINEERING(3:1:0), 8th Sem. Using only a simple resistor, they can directly be operated with line voltage, not requiring a transformer or other kind of lamp power supply. An intense arc is formed between electrod by applying high voltage. These are enclosed in a glass tube and xenon gas is filled under pressure. GAS DISCHARGES AND THEIR ... voltage of HID lamps can be reduced by as much as 56% when substituting pulsed voltage used for lamp ignition with AC voltage in 100 kHz range [7]. But when a moving object like rotating parts of machinery is followed, at the certain speed it may appear to be stationary or moving in series of jerks or rotating slowly than its actual speed. Learn and free practice physics general knowledge (gk) objective type questions & answers with explanation for all competitve exams and quiz. A power supply for a gas discharge lamp that provides a constant current to the lamp even when there are variations in a DC input voltage includes an inverter having a drive transformer that is controlled without negative feedback to operate close to its resonance condition, which permits a substantially constant load current even for large variations of the DC input voltage to the power supply. When concentrated chloride ions are present, chloride ions are in higher concentration than hydroxide ions, causing chloride ions to be preferentially discharged. A pinoybix mcq, quiz and reviewers. Simple gas-discharge tubes such as neon lamps exhibit electrical hysteresis. Understanding the characteristics of fluorescent and HID lamps makes it easier to recognize problems and simplifies corrective maintenance. Simple gas-discharge tubes such as neon lamps exhibit electrical hysteresis. are taking special care at the time of manufacture of bulbs which can withstand voltage fluctuation up to ± 20 per cent for a short period. a. When a voltage is applied, then the gas ionizes and starts to glow allowing a very small current to travel from one electrode to the other electrode. Physics is about an applied mathematics. 3. Gas discharge lamps, this meaning lamps using the principle to make a gas electrically con-ductive and thereby light emitting, are a relatively old technique. The most common of these tubes was called the thyratron. To stabilize the gas discharge c. To supply the power to the lamp d. Only a and c e. All of these The first arc lamp was invented by Sir Humphry Davy in the early 1800s, This lamp was designed with two carbon electrodes and 2,000 cells battery to generate the arc across a 4-inch gap in between two electrodes in air. ; However, in a dilute solution of sodium chloride, hydroxide ions give up electrons more readily than chloride ions. However, some manufacturers like M/s. G.E.C. Question is ⇒ The flicker effect of fluorescent lamps is more pronounced at, Options are ⇒ (A) lower frequencies, (B) higher frequencies, (C) lower voltages, (D) higher voltages, (E) , Leave your comments or Download question paper. Consequently the sodium vapour pressure in that region is reduced, leading to some ionisation of the neon gas filling, which causes an increase in discharge voltage and hence lamp power. Then, Ns/Np. Of course there's more to lighting maintenance than lamp replacement, particularly with discharge lamp systems. The most common of these tubes was called the thyratron. Multiple Choice Question (MCQ) of Electronics page-17:241. Control gear for high pressure discharge lamps Transformers for low voltage lamps Digital dimming ... Electronic ballasts have a reduced level of self-heating (a lower lamp temperature increases the efficiency of the lamp). Discharge tube: current vs. voltage characteristic. MCQ in Vacuum Tubes Part 2 as part of the Electronics Engineering Board Exam. Ask your interesting physics related questions for free. Lamps Used in Mines: Type # 2. Especially fluorescent lamps represent a very widespread lighting system. This high voltage pulse makes the xenon gas ionized sufficiently. B.Tech(Electrical), VSSUT ... Breakdown in non-uniform field and corona discharges, Post breakdown phenomena and applications, practical considerations in using gases for insulation purposes. Radiant efficiency of the luminous source depends on,2.Light waves travel with a velocity of,3.Carbon arc lamps are commonly used in,4.The unit of solid angle is-steradian, 5.Candela is the unit of-Luminous intensity.etc All gas discharge lamps operated on a 50 Hz alternating current supply are really flickering off and on 100 times per second. In an effort to raise the temperature at the U-bend Thorn's original lamps had a constricted tube diameter at that point, to bring the glass closer to the discharge. High-intensity discharge lamps (HID lamps) are a type of electrical gas-discharge lamp which produces light by means of an electric arc between tungsten electrodes housed inside a translucent or transparent fused quartz or fused alumina arc tube. Lighting maintenance is easy; just replace burned-out lamps." If voltage is reduced from 230 V to 200 V for a fluorescent tube light, it will result in a) reduced power consumption b) ... to stabilize the gas discharge c) to supply power to the lamp at supply frequency d) to supply power to the lamp at very high frequency 48. The graph is only typical however in the sense that all tubes exhibit the conduction behaviour shown, but the corresponding voltages and currents, and the relative lengths of the various regions, are highly variable. The gas performs several key functions in lamp operation, the most important of which are the following: It reduces the required starting voltage for the discharge, such that it can be easily struck on simple control gear. The voltage across the terminals of a battery, for example, is less than the emf when the battery supplies current, and it declines further as the battery is depleted or loaded down. Corona Mcq’s Interview ... A. Corona takes place at a voltage lower than breakdown voltage B. Corona takes place at a voltage higher than breakdown voltage C. Corona is a current phenomenon D. Corona increases the transmission line ... Q.7 Corona loss can be reduced by the use of hollow conductor because. One can then start to partition the data into 0 to 20 ms (or whatever period the voltage has) sections e.g. High voltage is fed to the lamp from the ballast by using the phenomenon of superimposing a low energy high voltage pulse. To ignite the lamp b. Therefore, hydroxide ions are preferentially discharged to form colourless, odourless oxygen gas.
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