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Easy

Question

A long straight wire of resistance R, radius ‘a’ and length ‘l’ carries a constant current ‘I’. The pointing vector for the wire will be

  1. fraction numerator I R over denominator 2 pi a l end fraction    
  2. fraction numerator I R to the power of 2 end exponent over denominator a l end fraction    
  3. fraction numerator I to the power of 2 end exponent R over denominator a l end fraction    
  4. fraction numerator I to the power of 2 end exponent R over denominator 2 pi a l end fraction    

The correct answer is: fraction numerator I to the power of 2 end exponent R over denominator 2 pi a l end fraction

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In the first transition series M n left parenthesis 3 d to the power of 5 end exponent 4 s to the power of 2 end exponent right parenthesis shows the maximum oxidation state of + 7.
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(ii)N i to the power of plus 2 end exponentd to the power of 8 end exponent2
(iii)C o to the power of plus 2 end exponentd to the power of 7 end exponent3
(iv)F e to the power of plus 2 end exponentd to the power of 6 end exponent4
mu equals square root of n left parenthesis n plus 2 right parenthesis end root (magnetic moment)
mu proportional to square root of n
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C u to the power of plus 2 end exponent
S.NoIonElectronic configurationNo. of unpaired electrons
(i)C u to the power of plus 2 end exponentd to the power of 9 end exponent1
(ii)N i to the power of plus 2 end exponentd to the power of 8 end exponent2
(iii)C o to the power of plus 2 end exponentd to the power of 7 end exponent3
(iv)F e to the power of plus 2 end exponentd to the power of 6 end exponent4
mu equals square root of n left parenthesis n plus 2 right parenthesis end root (magnetic moment)
mu proportional to square root of n
C u to the power of plus 2 end exponent there is only 1 unpaired electron so its magnetic moment is least.
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In first transition series, the melting point of M n is low because

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stack M n O with text basic end text below stack M n subscript 3 end subscript O subscript 4 end subscript with text amphoteric end text below stack M n subscript 2 end subscript O subscript 3 end subscript with text amphoteric end text below stack M n O subscript 2 end subscript with text amphoteric end text below stack M n subscript 2 end subscript O subscript 7 end subscript with text acidic end text below

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stack M n O with text basic end text below stack M n subscript 3 end subscript O subscript 4 end subscript with text amphoteric end text below stack M n subscript 2 end subscript O subscript 3 end subscript with text amphoteric end text below stack M n O subscript 2 end subscript with text amphoteric end text below stack M n subscript 2 end subscript O subscript 7 end subscript with text acidic end text below
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This configuration is more stable because of symmetrical distribution of e and exchange energy.
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