Q:
      
      
         
            
Bright light is found to emit from photographer’s flashgun. This brightness is due to the presence of which one of the following noble gases?
         
       
      
      
      
          
      
      
          Answer & Explanation
         Answer: B) Xenon         
         
Explanation: Electronic Flash differs from the consumable bulb flash in important aspects. Instead of creating light by burning up in an atmosphere containing oxygen, a consumable material (each bulb being used therefore only once), it produces a brilliant incandescent by discharging a current for a brief instant through a rarified gas, usually xenon. The gas glows every time the discharge is made through it but it is not consumed, so that many thousands of flashes are obtainable from a single tube, which helps to offset the much higher cost of the initial apparatus.
       
      
      
      
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