Final answer:
If the shunt resistance is larger than the resistance of the galvanometer, the sensitivity of the meter decreases, as it measures a smaller proportion of the total current and becomes less capable of measuring larger currents without risk of damage.
Step-by-step explanation:
If the shunt resistance is larger than the resistance of the galvanometer, then the correct answer is (C) The sensitivity decreases. A shunt resistor is used in conjunction with a galvanometer to convert it into an ammeter. When you increase the shunt resistance, less current is diverted away from the galvanometer, which means the galvanometer will measure a smaller proportion of the total current. As a result, the meter becomes more sensitive to small currents since the galvanometer is now acting on a larger fraction of the current. However, this increased sensitivity comes at the cost of not being able to measure large currents (since these could damage the galvanometer). In reality, we normally want to measure larger currents without damaging the galvanometer, so a small shunt resistance is used to ensure most of the current bypasses the galvanometer.