COMEDK · Physics · 21. Magnetic Effects of Current
To increase the current sensitivity of a moving coil galvanometer by \(25 \%\), its resistance is increased so that the new resistance becomes twice its initial resistance. By what factor does the voltage sensitivity change?
- A Decreases by \(37.5 \%\)
- B Increases by \(37.5 \%\)
- C Decreases by \(62.5 \%\)
- D Increases by \(62.5 \%\)
Answer & Solution
Correct Answer
(A) Decreases by \(37.5 \%\)
Step-by-step Solution
Detailed explanation
The current sensitivity of a moving coil galvanometer is given by \(I_s = \dfrac{\theta}{I} = \dfrac{NAB}{k}\), where \(N\) is the number of turns, \(A\) is the area, \(B\) is the magnetic field, and \(k\) is the torsional constant of the spring. The voltage sensitivity is given…
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