In this unit analogy, “Current is to Ampere as ______ is to ______”. Select the physical quantity and its SI unit that follow the same relationship as electric current and ampere.

Introduction / Context:
This analogy involves physics concepts and SI units. The pair “Current : Ampere” links a physical quantity (electric current) with its standard SI unit (ampere). We must select another pair where the first term is a well known physical quantity and the second term is its correct SI unit, creating an analogous relationship.

Given Data / Assumptions:

• Known pair: Current → Ampere. • Unknown pair: ? → ? • Options: Air : Kilogram, Work : Joule, Pressure : Speed, Temperature : Metre. • We assume standard SI units used in basic physics: ampere for current, joule for work, pascal for pressure, kelvin for temperature, and metre for length.

Concept / Approach:
The central idea is “physical quantity : its SI unit”. Electric current is measured in amperes. For the analogy to hold, the second pair must follow “another physical quantity : its own SI unit”. We review each option to see which one correctly matches. Many options deliberately pair a quantity with an incorrect or unrelated unit to test conceptual clarity.

Step-by-Step Solution:
Step 1: Confirm the first relationship. Electric current is a physical quantity that we measure using the SI unit ampere (symbol A). Step 2: Examine each option. Air : Kilogram – air is a mixture of gases; kilogram is a unit of mass, not a specific SI unit dedicated to air. Work : Joule – work is a physical quantity; its SI unit is the joule (symbol J), which equals newton metre. Pressure : Speed – pressure and speed are both physical quantities; neither is a unit of the other. Temperature : Metre – temperature is measured in kelvin (or degrees Celsius in everyday use), not in metres, which measure length. Step 3: Only Work : Joule matches the pattern “quantity : correct SI unit”.

Verification / Alternative check:
We can write out the valid SI pairs: current–ampere, work–joule, pressure–pascal, temperature–kelvin, length–metre. The only combination in the options that appears exactly as a valid SI pair is work–joule. Air–kilogram is not a standard physical quantity–unit pair and the other options mix distinct quantities or mismatched units. This confirms that work : joule is the correct parallel to current : ampere.

Why Other Options Are Wrong:
• Air : Kilogram – kilogram measures mass; air is not a specific physical quantity defined by kilogram alone. • Pressure : Speed – both are quantities, so the second is not a unit of the first; they cannot stand in the same relation. • Temperature : Metre – metre measures length, not temperature, which breaks the quantity–unit relationship.

Common Pitfalls:
Students sometimes overlook the requirement that the second word must be a unit, not another quantity. Another common error is confusing everyday associations (for example, thinking of air and kilograms in terms of weight) with formal SI definitions. Keeping a short mental list of core SI pairs helps quickly identify the only option here that fits: work and joule.

Final Answer:
The correct related pair is Work : Joule.