MCQ
A galvanometer having a coil resistance $100 \;\Omega$ gives a full scale deflection when a current of $1 \;\mathrm{mA}$ is passed through it. What is the value of the resistance which can convert this galvanometer into a voltmeter giving full scale deflection for a potential difference of $10\; \mathrm{V} ?$......$k\Omega$
  • A
    $9.9$
  • B
    $8.9$
  • C
    $7.9$
  • D
    $10$

Answer

$\mathrm{i}_{\mathrm{g}}=1 \mathrm{mA}, \mathrm{R}_{\mathrm{g}}=100 \Omega$

$\mathrm{V}=\mathrm{i}_{\mathrm{g}}\left(\mathrm{R}+\mathrm{R}_{\mathrm{g}}\right)$

$10=1 \times 10^{-3}(\mathrm{R}+100)$

$\mathrm{R}=9.9 \mathrm{k} \Omega$

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