Question

Match the device with its working principle:
 

List-1	List-2
a. Bourdon gauge	V. Deformation of element
b. Pirani gauge	I. Thermal conductivity
c. Semiconductor strain gauge	III. Piezo resistive effect
d. Bi-metallic strip	II. Thermal coefficient of expansion

• A. a–V, b–I, c–II, d–III
• B. a–V, b–II, c–III, d–I
• C. a–V, b–I, c–III, d–II
• D. a–V, b–III, c–I, d–II

Hint:

Always associate deformation with mechanical sensors, thermal conductivity with Pirani gauges, and piezo resistive/electric effects with strain or vibration-based sensors.

Answer 1

The Correct Option is C

To match each device with its corresponding working principle, we can summarize the principles as follows:

• Bourdon gauge: This device operates based on the deformation of element (V). It measures pressure by the bending of a coiled tube which straightens out as pressure is applied.
• Pirani gauge: It functions based on thermal conductivity (I). It measures low pressures by determining thermal conductivity of gases.
• Semiconductor strain gauge: This device uses the piezo resistive effect (III). It measures strain via change in resistance as strain is applied to a semiconductor material.
• Bi-metallic strip: Utilizes the thermal coefficient of expansion (II). It consists of two metals with different expansion rates, bending with temperature changes to function in thermostats.

Thus, the correct matching is:

a–V, b–I, c–III, d–II