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NEET PHYSICSMOVING CHARGES AND MAGNETISMMedium

Question

The resistance of an ammeter is 13 \Omega and its scale is graduated for a current up to 100 A. After an additional shunt has been connected to this ammeter, it becomes possible to measure currents up to 750 A by this ammeter. The value of shunt resistance is:

A

20 \Omega

B

2 \Omega

C

0.2 \Omega

D

2 k\Omega

Step-by-Step Solution

  1. Concept: An ammeter (or galvanometer) with resistance RGR_G and full-scale deflection current IgI_g can have its range extended to measure a larger current II by connecting a low resistance shunt (SS) in parallel with it .
  2. Formula: The potential drop across the galvanometer and the shunt is the same in a parallel combination. Therefore: IgRG=(I−Ig)SI_g R_G = (I - I_g) S Rearranging for the shunt resistance SS: S=IgRGI−IgS = \frac{I_g R_G}{I - I_g}
  3. Given Values:
  • Resistance of the initial meter (RGR_G) = 13 \Omega
  • Initial full-scale current (IgI_g) = 100 A
  • New full-scale current (II) = 750 A
  1. Calculation: S=100×13750−100S = \frac{100 \times 13}{750 - 100} S=1300650S = \frac{1300}{650} S=2 ΩS = 2 \, \Omega

Exam Context & Concepts Covered

This question aligns with the NEET PHYSICS syllabus, specifically targeting concepts from MOVING CHARGES AND MAGNETISM. Mastering this topic is crucial for scoring well in the upcoming medical entrance examinations. Solving conceptually related problems will help you understand the nuances of these concepts and improve your problem-solving speed.

PHYSICSMOVING CHARGES AND MAGNETISMresistanceammetergraduatedcurrentadditional

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