Ammeter is related to Current as a measuring instrument. In the same way, an Odometer is related to which physical quantity?

Introduction / Context:
This analogy is based on scientific instruments and the quantities they measure. In physics and basic science, students learn names of instruments such as ammeter, voltmeter, odometer, and so on. The pair Ammeter and Current is given, and you must extend the same relationship to Odometer and the quantity it measures. This is a standard style of question in aptitude and general science sections.

Given Data / Assumptions:
1) An ammeter is a device used to measure electric current in a circuit.
2) The first pair shows instrument to measured quantity, that is Ammeter to Current.
3) An odometer is a device fitted in vehicles that records the total distance travelled by the vehicle.
4) Options (reconstructed to improve clarity) are Distance travelled, Time taken, Pressure, and Speed.
5) Exactly one option should name the primary quantity measured by an odometer.

Concept / Approach:
The key concept is to focus on what the instrument directly reads. In a car or motorcycle, the odometer value increases as the vehicle moves and tells you how many kilometres or miles it has covered. That is total distance travelled, not instantaneous speed, and not time or pressure. A different device, the speedometer, is used for speed. We therefore map odometer to distance travelled in the same way that ammeter maps to current.

Step-by-Step Solution:
Step 1: Rephrase the first pair. An ammeter measures electric current in amperes. Step 2: Identify the relationship as instrument to measured quantity. Step 3: Recall what an odometer does in a vehicle dashboard. It counts how far the vehicle has travelled from a starting point and displays total distance. Step 4: Compare this with the options. Distance travelled directly matches what the odometer displays, often in kilometres or miles. Step 5: Time taken is measured by clocks, stopwatches, and timers, not by an odometer. Step 6: Pressure is measured by a manometer or pressure gauge. Step 7: Speed is measured by a speedometer, a related but distinct instrument from the odometer. Step 8: Therefore, the only correct parallel is Odometer to Distance travelled.

Verification / Alternative check:
Check common vehicle dashboards. You usually see two separate dials or displays. The speedometer needle or digital readout shows how fast you are going at that moment, and the odometer number shows how many kilometres or miles have been covered in total. This real world check confirms that distance, not speed, is the direct reading of the odometer.

Why Other Options Are Wrong:
Time taken has no direct connection to odometer readings. Although you could in theory combine odometer distance with a clock to calculate average speed, the odometer itself does not show time. Pressure is a physical quantity measured in pascals or bar, not something associated with an odometer. Speed is close in context to vehicles but uses a different device, the speedometer. Choosing speed would confuse two distinct instruments.

Common Pitfalls:
Many learners confuse odometer with speedometer because both appear on the dashboard. They may see a dial in the car and assume it is one combined device. In fact, the odometer accumulates distance while the speedometer shows instantaneous speed. Remembering this distinction is important in physics and in solving analogy questions correctly.

Final Answer:
Thus, the correct completion of the analogy is Ammeter is to Current as Odometer is to Distance travelled.