Microphone is to loud as microscope is to which of the following actions or effects.

Introduction / Context:
This analogy is based on the function of instruments. A microphone is connected with sound and loudness, while a microscope is connected with vision and the size of what we see. The question asks which verb describes what a microscope does, in the same way that loud describes the effect a microphone helps produce. Understanding the functions of common devices is essential for solving such questions.

Given Data / Assumptions:

• First pair: Microphone : loud.
• A microphone amplifies sound so that it can be heard loudly.
• Second item: Microscope : ?
• Options: Investigate, Magnify, Examine, Elongate.
• We consider the primary effect or action associated with a microscope.

Concept / Approach:
Microphone is an instrument that makes sound louder; its main function is amplification. Therefore, loud is the result it helps to achieve. A microscope is an instrument that makes very small objects appear larger and clearer to the eye. The technical term for this action is magnify. Investigate and examine are activities performed by scientists or observers using a microscope, but they are not the direct optical effect. Elongate means to make something longer, which is not specifically what a microscope does. So the best parallel is microscope : magnify.

Step-by-Step Solution:
Step 1: Describe the first pair in a sentence. A microphone is used to make sound loud. Step 2: Ask what a microscope is used for in a similar way. The answer is that it makes tiny things look bigger. Step 3: Identify the verb that means make larger in appearance, which is magnify. Step 4: Compare magnify with investigate, examine and elongate and note which one refers to an actual optical effect. Step 5: Conclude that magnify best mirrors the relationship between device and result.

Verification / Alternative check:
We can rephrase both pairs in parallel sentences. “A microphone makes sound loud” and “A microscope magnifies objects.” These two sentences show a clear and consistent relationship: instrument and effect. If we tried to fit investigate instead, we would say “A microscope investigates objects,” which is not accurate; people investigate, not instruments by themselves. “A microscope examines objects” is closer but still describes what a user does rather than the optical process. “A microscope elongates objects” is simply incorrect. Therefore magnify is the only choice that truly matches the pattern.

Why Other Options Are Wrong:

• Investigate: Refers to a human activity of inquiry; a microscope is a tool in that process but does not investigate on its own.
• Examine: Also a user action; scientists examine samples using a microscope but the instrument itself magnifies.
• Elongate: Means to make longer in one dimension, which is not the specific function of a microscope.

Common Pitfalls:
Candidates often pick examine because it sounds like what happens in a laboratory. However, analogy questions usually look for the precise functional relationship, not just any associated action. Always focus on what the instrument physically does. With microphone, that is amplification of sound; with microscope, that is magnification of small objects.

Final Answer:
The correct completion is Microscope : Magnify, giving the analogy Microphone : loud :: Microscope : magnify.