Question

Match List-I with List-II.

List-I		List-II
Instrument		Parameter measurement
(A)	Gypsum blocks	(I)	Water flow
(B)	Flume	(II)	Soil moisture suction
(C)	Infra-red balance	(III)	Di-electric constant
(D)	Irrometer	(IV)	Electric resistance
(E)	TDR	(V)	Gravimetric moisture content

Choose the correct answer from the options given below.

• (A) - (IV), (B) - (III), (C) - (II), (D) - (V), (E) - (I)
• (A) - (IV), (B) - (III), (C) - (I), (D) - (II), (E) - (V)
• (A) - (I), (B) - (V), (C) - (IV), (D) - (II), (E) - (III)
• (A) - (IV), (B) - (I), (C) - (V), (D) - (II), (E) - (III)

Hint:

Think about the physical quantity each instrument's reading actually comes from, resistance, flow depth, weight loss, suction, or pulse timing.

Answer 1

The Correct Option is D

Step 1: Understanding the Question:
We need to match five field instruments used in soil and water measurement with the actual physical parameter each one measures.

Step 2: Key Formula or Approach:
Work through each instrument's operating principle one at a time rather than guessing from the name alone, since several names sound similar to the parameters.

Step 3: Detailed Explanation:
(A) Gypsum blocks: these porous blocks equilibrate their moisture with the surrounding soil, and the reading is taken as the electric resistance across two embedded electrodes, resistance falls as the block wets up. So (A) matches (IV) Electric resistance.
(B) Flume: a flume is a shaped, open channel structure placed in a stream or canal specifically to measure the rate of water flow passing through it from the water depth in the flume. So (B) matches (I) Water flow.
(C) Infra-red balance: this device dries a small soil sample rapidly using an infra-red lamp while it sits on an analytical balance, and the weight lost on drying gives the classic oven-drying style gravimetric moisture content. So (C) matches (V) Gravimetric moisture content.
(D) Irrometer: this is the trade name for a tensiometer, a water filled tube with a porous ceramic tip that registers the suction (tension) with which soil holds its water. So (D) matches (II) Soil moisture suction.
(E) TDR (Time Domain Reflectometry): as covered earlier, TDR times a fast pulse traveling through a probe to find the soil's apparent dielectric constant, which is then converted to water content. So (E) matches (III) Di-electric constant.
Putting these five pairs together gives (A)-(IV), (B)-(I), (C)-(V), (D)-(II), (E)-(III), which is option 4. The other options mismatch at least one instrument, for example placing the flume against suction or dielectric constant instead of water flow.

Step 4: Final Answer:
(A)-(IV), (B)-(I), (C)-(V), (D)-(II), (E)-(III), matching option 4.