The Moving Coil Galvanometer

Step 1: Sensitivity of a galvanometer.
The sensitivity of a moving coil galvanometer is given by , where is the number of turns, and is the current.
Step 2: Increasing number of turns.
When the number of turns ( ) increases, the coil generates a stronger magnetic field, which increases the deflection for the same current. Hence, the sensitivity increases.
Step 3: Elimination.
- (A) increases: Correct, as sensitivity is directly proportional to the number of turns.
- (B) decreases: Incorrect, sensitivity increases with more turns.
- (C) remains unchanged: Incorrect, as increasing turns does affect sensitivity.
- (D) may increase or may decrease: Incorrect, it always increases.
Step 4: Conclusion.
Thus, increasing the number of turns in a galvanometer increases its sensitivity.