Why it the tungsten–halogen lamp more efficient than a normal tungsten filament lamp?

1.Why it the tungsten–halogen lamp more efficient than a normal tungstenfilament

 

lamp?2. Explain in simple terms how electromagnetic radiation is emitted from a lowpressure gas or vapour when an electric current is flowing in it. Indicate how current can flow in the gas or vapour. 3.Why is a ballast needed for the operation of a discharge lamp? Explain why a

ballast used will be more efficient if it takes the form of choke rather than a resistor.

 

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Sketch the load characteristics, terminal voltage/load current, of the following types of DC generator

1. (a) Sketch the load characteristics, terminal voltage/load current, of the following types of DC generator: (i) series-connected, (ii) shunt-connected and (iii) compound-connected.   (b) State one purpose for which….

what happens if the resistance in series with the shunt field of a DC motor is increased in value

1. Sparking at the trailing edges of the brushes in a DC machine is usually prevented by fitting   (a) copper gauze brushes (b) a compensating winding (c) a compound….

Calculate the synchronous speed of a 10-pole three-phase machine connected to a 50 Hz supply.

1. The generator characteristic shown in Figure 9.28 is for a   (a) shunt machine (b) series machine (c) differentially compounded machine (d) cumulatively compounded machine 2.The speed of a….