Question

Which of the following thermocouple is capable of measuring highest temperature?
1. Chromel-alumel
2. Platinum-rhodium
3. Iridium-rhodium
4. Iron-constantan

Answer 1

Correct Answer - Option 3 : Iridium-rhodium

Concept:

• A Thermocouple is a sensor used to measure temperature.
• Thermocouples consist of two wire legs made from different metals.
• The wire's legs are welded together at one end, creating a junction.
• This junction is where the temperature is measured.
• When the junction experiences a change in temperature, a voltage is created.
• The voltage can then be interpreted using thermocouple reference tables to calculate the temperature.
• Type of thermocouple:

1. Chromel-alumel: It can measure temperature in the range of –270 to 1260°C
2. Platinum-rhodium: It can measure temperature in the range of 0 to 1500 °C
3. Iridium-rhodium: It can measure temperature up to 2148°C
4. Iron-constantan: It can measure temperature in the range of -40 to 750 °C