For what value of R will the current in the galvanometer be zero?
Correct answer: D. 1Ω
- A. 5Ω
- B. 2Ω
- C. 7Ω
- D. 1Ω
Explanation
To find the value of R at which the galvanometer reads zero current, one can apply Kirchhoff's laws or the principle of a balanced Wheatstone bridge. The condition for zero current implies that the potential difference across the galvanometer is zero, leading to the equation:V = IR, where I = V/R = 12/(R+5).Setting the potential difference across R equal to 2V, we have: 2V = 12/(R+5) × R.Simplifying gives R + 5 = 6R, which results in R = 1. Thus, 1Ω is the correct value for R.The other options (5Ω, 2Ω, and 7Ω) do not satisfy this balanced condition, and hence they yield non-zero current in the galvanometer.
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