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NEET Sample Paper NEET Sample Test Paper-65

  • question_answer
    A moving coil galvanometer has 48 turns and area of coil is\[4\,\,\times \,\,{{10}^{-\,2}}{{m}^{2}}\]. If the magnetic field is 0.2 T, then to increase the current sensitivity by \[25\,%\] without changing area and field the number of turns should become      

    A) 24                                

    B) 36        

    C) 60                                

    D) 54        

    Correct Answer: C

    Solution :

    As we know \[Current\text{ }sensitivity\text{ }{{S}_{1}}\,\,=\,\,\frac{NBA}{C}\] Current sensitivity 5, == ?? \[\Rightarrow \,\,\,{{S}_{1}}\,\,\propto \,\,N\,\,\,\Rightarrow \,\,\,\frac{{{({{S}_{i}})}_{1}}}{{{({{S}_{i}})}_{2}}}\,\,=\,\,\frac{{{N}_{1}}}{{{N}_{2}}}\,\,\,\Rightarrow \,\,\frac{100}{125}\,\,=\,\,\frac{48}{{{N}_{2}}}\] \[\Rightarrow \,\,\,{{N}_{2}}=60\]


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