Question

Given below are two statements, one labelled as Assertion (A) and the other labelled as Reason (R).
Assertion (A): In a double ring infiltrometer, the double ring avoids requirement of deep insertion into the soil.
Reason (R): The outer ring provides a buffer of infiltrating water, which leads to the force of infiltration below the inner ring remaining completely vertical and unidirectional.
In light of the above statements, choose the correct answer from the options given below.

• A. Both (A) and (R) are true and (R) is the correct explanation of (A).
• B. Both (A) and (R) are true but (R) is NOT the correct explanation of (A).
• C. (A) is true but (R) is false.
• D. (A) is false but (R) is true.

Hint:

Insertion depth requirements do not change with a double ring, the outer ring's real job is stopping sideways spreading of water under the inner ring.

Answer 1

The Correct Option is D

This assertion-reason question is really asking what the outer ring of a double ring infiltrometer is actually for.

1. Assertion (A): it claims the double ring design means the rings do not need to be pushed deep into the soil. This is not correct, every infiltrometer ring, whether single or double, must still be inserted deep enough to stop water leaking along the ring wall, adding a second ring does not reduce this depth requirement.
2. Reason (R): it says the outer ring keeps a buffer of water around the inner ring, forcing the water below the inner ring to travel straight down instead of spreading sideways. This matches exactly why double ring infiltrometers were designed, so this statement is true.

So we have a false assertion paired with a true reason, meaning the reason cannot possibly explain the assertion since the assertion itself does not hold.

Let's summarize:

• Ring insertion depth is a separate requirement from the number of rings used.
• The outer ring's genuine job is to buffer the inner ring's water so infiltration stays vertical and one directional.

So (A) is false and (R) is true, which is option 4.