A teacher in his physics laboratory allotted an experiment to determine the resistance G a galvanometer.…

A teacher in his physics laboratory allotted an experiment to determine the resistance G a galvanometer. Students took the observations for 13 deflection in the galvanometer. Which of the below is true for measuring value of G?
  1. 13 deflection method cannot be used for determining the resistance of the galvanometer.
  2. 13 deflection method can be used and in this case the G equals to twice the value of shunt resistance(s).
  3. 13 deflection method can be used and in this case, the G equals to three times the value of shunt resistance(s).
  4. 13 deflection method can be used and in this case the G value equals to the shunt resistance(s)

Solution

If a large resistance R is connected with a battery, then current will be approximately εR, and t will remain almost constant.

In 1st  case, only G is connected ⇒ig=i

In 2nd  case,

igR0=I-igS⇒ig2=SRg+Si

If ig2=13ig,⇒SRg+Si=13i

Rg=2S

Asked in: JEE Main 2022 (25 Jun Shift 1)

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