COMEDK · Physics · 19. Current Electricity
A galvanometer having 20 divisions has a resistance of \(50 \Omega\). A deflection of one division in this galvanometer needs a current of 0.2 mA . What should be the resistance that needs to be connected to this galvanometer to convert it to a voltmeter of range (0-20) volts?
- A \(4950 \Omega\) in series with the galvanometer
- B \(3950 \Omega\) in series with the galvanometer
- C \(4950 \Omega\) in parallel with the galvanometer
- D \(3950 \Omega\) in parallel with the galvanometer
Answer & Solution
Correct Answer
(A) \(4950 \Omega\) in series with the galvanometer
Step-by-step Solution
Detailed explanation
The full scale deflection current \(I_g\) of the galvanometer is calculated by multiplying the number of divisions by the current per division. \(I_g = 20 \times 0.2 \text{ mA} = 20 \times 0.2 \times 10^{-3} \text{ A} = 4 \times 10^{-3} \text{ A} = 0.004 \text{ A}\). The…
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