The resistance of a galvanometer

Question:

The resistance of a galvanometer is $50 \mathrm{ohm}$ and the maximum current which can be passed through it is $0.002 \mathrm{~A}$. What resistance must be connected to it order to convert it into an ammeter of range $0-0.5 \mathrm{~A}$ ?

  1. (1) $0.5 \mathrm{ohm}$

  2. (2) $0.002 \mathrm{ohm}$

  3. (3) $0.02 \mathrm{ohm}$

  4. (4) $0.2 \mathrm{ohm}$


Correct Option: , 4

Solution:

(4) Using, $i_{g}=i \frac{S}{S+G}$

$0.002=0.5 \frac{S}{S+50}$

On solving, we get

$S=\frac{100}{498} \simeq 0.2 \Omega$

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