Q54 / 66 · JEE Advanced 2008 (Paper 2) · Physics

Statement 1 The sensitivity of a moving coil galvanometer is increased by placing a suitable magnetic material as a core inside the coil. and Statement 2 Soft iron has a high magnetic permeability and cannot be easily magnetized or demagnetized.

  • A
    Statement 1 is true, Statement 2 is true, Statement 2 is a correct explanation for Statement 1.
  • B
    Statement 1 is true, Statement 2 is true, Statement 2 is not a correct explanation for Statement 1.
  • Correct answer
    C
    Statement 1 is true, Statement 2 is false.
  • D
    Statement 1 is false, Statement 2 is true

Solution

$c \phi=B I N A$ $$ \therefore \phi=\left(\frac{B N A}{c}\right) I $$ Using iron core, value of magnetic field increases. So, deflection increases for same current. Hence, sensitivity increases. Soft iron can be easily magnetized or demagnetized. $\therefore$ correct option is (c).

Hence, the correct answer is option: 'C'.

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