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The diagram shows a uniformly charged hemisphere of radius R. It has volume charge density rho. If the electric field at a point 2R distance above its centre is E then what is the electric field at the point which is 2R below its centre?
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  1. fraction numerator rho R over denominator 6 epsilon subscript 0 end subscript end fraction plus E  
  2. fraction numerator rho R over denominator 12 epsilon subscript 0 end subscript end fraction minus E  
  3. fraction numerator negative rho R over denominator 6 epsilon subscript 0 end subscript end fraction plus E  
  4. fraction numerator rho R over denominator 24 epsilon subscript 0 end subscript end fraction plus E  

    Answer:The correct answer is: fraction numerator negative rho R over denominator 6 epsilon subscript 0 end subscript end fraction plus E
    Apply principle of superposition
    Electric field due to a uniformly charged sphere =fraction numerator rho R over denominator 12 epsilon subscript 0 end subscript end fraction semicolon E subscript text reuliani  end text end subscript equals fraction numerator rho R over denominator 12 ϵ subscript 0 end subscript end fraction minus E

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