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Moving Charges and Magnetism — Physics STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 SciencePhysicsMoving Charges and Magnetism3 Marks
Question
  1. Define current sensitivity of a galvanometer. Write its expression.
  2. A galvanometer has resistance G and shows full scale deflection for current Ig.
  1. How can it be converted into an ammeter to measure current up to $I_0(I_0 > Ig)?$
  2. What is the effective resistance of this ammeter?
✓

Answer

  1. Current sensitivity: It is defined as the amount of deflection produced per unit magnitude of current passes.
$\text{C}_\text{s}=\frac{\phi}{\text{I}}\text{ or }\text{C}_\text{s}=\frac{\text{NAB}}{\mu,}$
  1.  
  1.  

(G) can be converted into an ammeter by connected a small stunt resistance parallel to (G) coil so that,
$\text{IgG}=\big(\text{I}_0-\text{I}_\text{g}\big)\text{S}$
$\therefore\text{S}=\frac{\text{IgG}}{\text{I}_0-\text{I}_\text{g}}$
  1. Effective resistance of $(\text{A})\Rightarrow\frac{\text{GS}}{\text{G}+\text{S}}$

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