I am aarthi .
 
When two resistors of resistance R1 and R2 are connected in parallel , the net resistance is 3 ohms . When connected in  series its value is 10 ohms . calculate the values of R1 and R2 .
 
kindly pose the answer for the above question .

Asked by palani002001 | 27th May, 2015, 08:19: AM

Expert Answer:

begin mathsize 14px style When space straight R subscript 1 space and space straight R subscript 2 space are space connected space in space parallel colon 1 over straight R subscript 1 plus 1 over straight R subscript 2 equals fraction numerator 1 over denominator 3 straight capital omega end fraction fraction numerator straight R subscript 2 straight R subscript 1 over denominator straight R subscript 2 plus straight R subscript 1 end fraction equals 3 space space minus negative negative negative negative negative negative negative negative negative negative left parenthesis 1 right parenthesis When space connected space in space series colon straight R subscript 1 plus straight R subscript 2 space equals 10 space minus negative negative negative negative negative negative negative negative negative left parenthesis 2 right parenthesis left parenthesis 2 right parenthesis space in space left parenthesis 1 right parenthesis space gives colon fraction numerator straight R subscript 2 straight R subscript 1 over denominator 10 end fraction equals 3 space space straight R subscript 2 straight R subscript 1 equals 30 R subscript 2 equals 30 over R subscript 1 minus negative negative negative negative negative negative left parenthesis 3 right parenthesis s u b space i n space left parenthesis 2 right parenthesis space w e space g e t colon straight R subscript 1 plus 30 over R subscript 1 space equals 10 end style
begin mathsize 14px style straight R subscript 1 squared plus 30 space equals 10 straight R subscript 1 straight R subscript 1 squared minus 10 straight R subscript 1 space plus 30 space equals 0 On space solving space this space we space will space end space up space in space imaginary space value space for space straight R end style
Which is not possible.So please check the value of net resistance given in the question when the resistors are connected in series and parallel.
The method to solve this question is as given above. Verify the value of net resistance.

Answered by Jyothi Nair | 27th May, 2015, 09:14: AM

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