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Question 1:

What is an RTD?

A) A device that measures temperature using a thermocouple
B) A type of resistance-based temperature sensor
C) A digital temperature measuring device
D) A device used to control electrical resistance in circuits

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Explanation: The correct answer is B) A type of resistance-based temperature sensor. An RTD (Resistance Temperature Detector) is a type of temperature sensor that uses the principle of electrical resistance change with temperature. The resistance of the RTD changes predictably with temperature, allowing for accurate temperature measurement.

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Question 2:

Which material is commonly used for RTDs?

A) Platinum
B) Copper
C) Aluminum
D) Iron

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Explanation: The correct answer is A) Platinum. Platinum is commonly used as the sensing element in RTDs due to its excellent stability, repeatability, and high temperature coefficient of resistance. It provides accurate and reliable temperature measurements over a wide temperature range.

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Question 3:

What is the typical resistance change of an RTD with temperature?

A) Linear
B) Exponential
C) Step-wise
D) No change

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Explanation: The correct answer is A) Linear. The resistance change of an RTD with temperature follows a linear relationship. As the temperature increases, the resistance of the RTD increases proportionally. This linear response allows for easy calibration and accurate temperature measurements.

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Question 4:

What is the temperature coefficient of an RTD?

A) The rate at which resistance changes with temperature
B) The maximum temperature that an RTD can measure
C) The range of temperatures an RTD can measure
D) The sensitivity of an RTD to environmental conditions

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Explanation: The correct answer is A) The rate at which resistance changes with temperature. The temperature coefficient of an RTD is a measure of how much the resistance changes per degree of temperature change. It indicates the sensitivity of the RTD to temperature variations and is typically expressed in units of ohms per degree Celsius (Ω/°C) or ohms per degree Kelvin (Ω/K).

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Question 5:

What is a disadvantage of using RTDs for temperature measurement?

A) High cost
B) Low accuracy
C) Limited temperature range
D) Fragility

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Explanation: The correct answer is A) High cost. One of the disadvantages of using RTDs for temperature measurement is their relatively high cost compared to some other temperature sensors. RTDs, particularly those made with platinum, can be more expensive to manufacture and purchase. However, their high accuracy and stability often make them the preferred choice in many applications despite the higher cost.