Description : The heated parts of an electrical machine dissipate heat into their surroundings by which of the following modes of heat dissipation ? (a) Conduction (b) Convection (c) Radiation (d) All ofthe above
Last Answer : (d) All ofthe above
Description : When a solid-state component of an electronic circuit is mounted to a metallic mass, the general purpose of that mass is to ____________. A. prevent vibration damage to delicate components B. prevent ... damage to solid-state components C. dissipate stray magnetic currents D. act as a heat sink
Last Answer : Answer: D
Description : If we could drop an F5 tornado in the middle of a hurricane, would that disrupt it enough to dissipate it?
Last Answer : It might just be absorbed by the hurricane and make it even stronger.
Description : Using your fingers to dissipate the foam on top of the beer: gross or not gross?
Last Answer : As long as it’s your own beer, I wouldn’t care. But keep your oily finger out of my beer.
Description : How long does it take chlorine to dissipate from treated water?
Last Answer : 24 hours should do it.
Description : If ghosts are made of energy, then why don't ghosts entropy or dissipate?
Last Answer : answer:Ghost myths simply don't adhere to the laws of science. If they were pure energy, they would also only last a certain amount of time thanks to Newton's Law of Exponential Decay. Anyone who ... if people want to believe in ghosts, but please don't muddy the name of science in the process.
Description : Is there a Home Remedy to eliminate or dissipate paint odor?
Last Answer : answer:Why would you want to dissipate it? Seriously though- knowing not everyone is an artist who enjoys the smell of paint- airing out is the best method. Sprays mask it but in reality the fumes need to ... fresh paint is not in the direct path of the fan so it does not blow dust onto the surface.
Description : Shading coils are installed on AC full-voltage starters to _____________. A. eliminate contact chatter B. dissipate opening contact arcs C. delay current build up in the holding coil D. protect the motor windings from momentary starting current overload
Last Answer : Answer: A
Description : What is meant by the term radiation resistance for an antenna? A. The resistance in the trap coils to received signal B. An equivalent resistance that would dissipate the same amount of power as ... antenna C. The specific impedance of the antenna D. Losses in the antenna elements and feed line
Last Answer : B. An equivalent resistance that would dissipate the same amount of power as that radiated from an antenna
Description : Select the option that is most nearly OPPOSITE in meaning to the word in BOLD. Don’t dissipate your strength on useless projects. (a) Conserve (b) Disperse (c) Dispel (d) Squander
Last Answer : (a) Conserve
Description : It is the resistance that, if it replaced the antenna, would dissipate exactly the same amount of power that the antenna radiates
Last Answer : . Radiation resistance
Description : Three equal resistors connected in series with a source of e m f together dissipate 10 W of power each. What will be the power dissipated if the same resistors are connected in parallel across the same source of e m f? a. 40 W b. 90W c. 100W d. 120W
Last Answer : b. 90W
Description : A waveguide termination having VSWR of 1.1 is used to dissipate 100 watts of power. The reflected power will be A) 0.2268 W B) 0.5868 W C) 0.3468 W D) 0.4568 W
Last Answer : A waveguide termination having VSWR of 1.1 is used to dissipate 100 watts of power. The reflected power will be 0.2268 W
Last Answer : If two parallel-connected resistors dissipate 6 watts and 10 watts of power, then 16 watts is the total power loss.
Last Answer : A 4 ῼ resistor carrying 2 Amp current will dissipate power equal to 16 watts.
Description : Drinks remain hot or cold for a long time in a thermos flask because of the (a) presence of air, which is a bad conductor of heat, in between the double walls (b) silver coating on the inside of the double walls (c) vacuum between the double walls (d) combined effects of (b) and (c)
Last Answer : Ans:(d)
Description : By what process is heat transmitted from the filament of an evacuated electric bulb to the glass? (a) Conduction (b) Convection (c) Radiation (d) Heat cannot be transmitted through vacuum
Last Answer : Ans:(c)
Description : Which of the following is not a feature of first generation computers A) They used vacuum tubes or valves as main electronic component B) They consumed lots of electricity and produced excessive heat C) They used machine language and assembly language to program the machine D) None of above
Last Answer : Answer : C
Description : What was the main disadvantage of vacuum tubes? A) They were larger in size B) They consumed a lot of electricity C) They produced heat and often burned out D) The operation cost was high
Description : Which waves cannot be transmitted through vacuum - (1) Light (2) Heat (3) Sound (4) Electromagnetic
Last Answer : (3) Sound Explanation: Sound waves cannot be transmitted through vacuum. It is transmitted by the movement of particles along with the direction of the motion of the sound wave. More generally, sound is a mechanical disturbance which is dependent upon a medium to travel.
Description : The velocity of heat radiation in vacuum is – (1) Equal to that of light (2) Less than that of light (3) Greater than that of light (4) Equal to that of sound
Last Answer : (1) Equal to that of light Explanation: Electrons are generally responsible for heat conduction. The phonons (vibrations of the nuclei) also play a part, depending on the temperature of the ... Electromagnetic radiation, which in a vacuum should go on forever at the speed of light theoretically.
Description : These waves cannot be trans-mitted through vacuum – (1) Light (2) Sound (3) Heat (4) Electromagnetic
Last Answer : (2) Sound Explanation: Sound is a mechanical wave that is created by vibrating objects and propagated through a medium from one location to another. Because mechanical waves rely on particle interaction ... space that are void of particles. That is, mechanical waves cannot travel through a vacuum.
Description : Which of the following statements comparing transistors and vacuum tubes is correct? A. Both transistors and vacuum tubes have a cathode that must be heated to give off electrons. B. A vacuum tube must ... flow. D. The anode of both transistors and vacuum tubes must be heated to give off electrons.
Last Answer : Answer: B
Description : Heat sinks are frequently used with _____________. A. power transistors B. vacuum tubes C. tunnel rectifier diodes D. all of the above
Description : Crude oil is subjected to vacuum distillation in the last stage, because (A) High boiling point products like heavy fuel oil & lubricating oils are heat sensitive and may decompose (B) Lighter/low ... prone to thermal decomposition (C) High purity products can be obtained thereby (D) None of these
Last Answer : (A) High boiling point products like heavy fuel oil & lubricating oils are heat sensitive and may decompose
Description : A dephlegmator is a (A) Total condenser (B) Vacuum evaporator (C) Partial condenser (D) Double pipe heat exchanger
Last Answer : (C) Partial condenser
Description : Pick out the wrong statement. (A) Heat transfer by radiation cannot occur across an absolute volume (B) In case of a shell and tube heat exchanger, the pressure drop through the shell is ... The amount of heat involved in the condensation or vaporisation of 1 kg of a fluid is the same
Last Answer : (A) Heat transfer by radiation cannot occur across an absolute volume
Description : Vacuum is generally maintained in the vapour space of an evaporator mainly to (A) Get economical temperature difference by using moderate pressure steam (B) Facilitate forward ... (C) Concentrate heat sensitive materials (D) Achieve very high concentration of the final product
Last Answer : (A) Get economical temperature difference by using moderate pressure steam
Description : Heat waves (A) Cannot pass through vacuum (B) Travel in straight line (C) Can be reflected by a mirror (D) Both (B) and (C)
Last Answer : (D) Both (B) and (C)
Description : In case of evaporators, liquid entrainment results primarily due to (A) High vacuum in the evaporator (B) High evaporation rate (C) Foaming of the solution (D) High heat transfer rate
Last Answer : (C) Foaming of the solution
Description : Heat sensitive materials can be concentrated in an evaporator employing (A) Vacuum (B) High pressure (C) High residence time (D) None of these
Last Answer : (A) Vacuum
Description : Pick out the wrong statement (A) Phase rule variables are intensive properties (B) Heat and work are both state function (C) The work done by expansion of a gas in vacuum is zero (D) CPand CVare state function
Last Answer : (B) Heat and work are both state function
Description : A unit of pressure used in high vacuum technology, which is equal to 1mmhg. a. specific heat b. isometric c. isobaric d. torr
Last Answer : torr
Description : When welding medium carbon steel plates over 100mm in thickness would the basic electrodes require any pre treatment before use? a) None if they were in a vacuum pack opened 8 hours prior to use b) None if ... ) Heat to 500 °C for 2 hours if used outside d) Baked at 150°C for 4hours prior to use
Last Answer : b) None if they were in a sealed vacuum pack prior to use
Description : Why is a vacuum breaker used on shell and tube heat exchangers that are utilizing steam as the heating utility?
Last Answer : Vacuum breakers are often installed on the shell side (steam side) of shell and tube exchangers to allow air to enter the shell in case of vacuum conditions developing inside the shell. For an ... vacuum in the shell could allow condensate to build in the unit and water hammer may result.
Description : Which of the following statements regarding evacuated tube collectors (ETC) are true? i) ETC is used for high temperatures upto 150oC ii) because of use of vacuum between two concentric glass tube, higher amount of heat is ... upon the ambient temperature i & iii b) ii & iii c) i & iv d) i & ii
Last Answer : d) i & ii
Description : Low-temperature ____ evaporators are used for heat-sensitive foods. a. ultrafiltration c. vacuum b. osmosis d. drum
Last Answer : c. vacuum
Description : These waves cannot be transmitted through vacuum (1) Light (2) Sound (3) Heat (4) Electromagnetic
Last Answer : Sound
Description : The velocity of heat radiation in vacuum is (1) Equal to that of light (2) Less than that of light (3) Greater than that of light (4) Equal to that of sound
Last Answer : Equal to that of light