Q.52 Match the instruments in Group I with their corresponding measurements in Group II.
   Group I                                         Group II
P. Manometer                          1. Agitator speed
Q. Rotameter                           2. Pressure difference
R. Tachometer                         3. Cell number
S. Haemocytometer                4. Air flow rate
(A) P–4, Q–1, R–2, S–3 (B) P–3, Q–4, R–1, S–2
(C) P–2, Q–4, R–1, S–3 (D) P–2, Q–1, R–4, S–3

Correct Answer: (C) P-2, Q-4, R-1, S-3

Manometer measures pressure difference, rotameter measures air flow rate, tachometer measures agitator speed, and haemocytometer counts cells. This matching aligns perfectly with standard biotechnology and chemical engineering instrument uses.​

Instrument Functions

Manometer detects pressure differences using liquid columns, vital for fluid dynamics in bioreactors. Rotameter quantifies gas flow via a floating indicator in a tapered tube. Tachometer gauges rotational speed of agitators in fermentation setups. Haemocytometer tallies microbial cell numbers in a ruled chamber under microscopy.​

Option Analysis

• (A) P-4, Q-1, R-2, S-3: Wrong; manometer does not measure agitator speed (P-4 mismatch), rotameter not for pressure (Q-1 error).

• (B) P-3, Q-4, R-1, S-2: Incorrect; manometer unfit for cell counting (P-3 wrong), haemocytometer ignores pressure (S-2 mismatch).

• (C) P-2, Q-4, R-1, S-3: Correct; each pairs accurately with primary functions in lab contexts.

• (D) P-2, Q-1, R-4, S-3: Flawed; rotameter not for agitator speed (Q-1 error), tachometer not flow rate (R-4 wrong).​

Introduction to Instrument Matching

In biotechnology and chemical engineering exams like GATE, questions test precise matching of instruments in Group I (manometer, rotameter, tachometer, haemocytometer) to measurements in Group II (agitator speed, pressure difference, cell number, air flow rate). Correct pairing, such as P-2, Q-4, R-1, S-3, demands understanding core lab functions for fermentation, cell culture, and fluid handling.​

Core Instrument Roles

• Manometer (P) links to pressure difference (2) via U-tube liquid deflection, essential for bioreactor pressure gradients.

• Rotameter (Q) pairs with air flow rate (4), using variable area for sterile gas sparging in fermenters.

• Tachometer (R) measures agitator speed (1), ensuring optimal mixing RPM in microbial growth vessels.

• Haemocytometer (S) counts cell number (3), via Neubauer grid for viability in suspension cultures.​

Exam Strategies for Matching MCQs

Analyze options systematically: verify manometer against pressure, eliminate mismatches like rotameter for speed. Practice reinforces biotech lab standards, boosting accuracy in competitive tests. Common pitfalls include confusing flow tools with speed meters.​