Operating range of a temperature measuring instrument is 800 to 1600°C. It could be a/an __________ pyrometer.

The correct answer is: B. Optical

✅ Explanation:
An instrument with an operating range of 800°C to 1600°C is used for high-temperature measurement, where contact methods (like thermocouples) may not be feasible or accurate. This temperature range is typical for optical pyrometers.

Option Breakdown:
A. Radiation Pyrometer
Measures total thermal radiation from an object.

Can operate over a wide range, including lower temperatures (~300°C and above).

While usable, it's less precise than optical pyrometers at higher temperatures.
❌ Not the best fit for the specific range.

B. Optical Pyrometer ✅
Designed for high temperatures, usually above 700°C.

Works by matching the brightness of a filament to the brightness of the hot object (disappearing filament method).

Ideal for 800–1600°C, especially in metallurgical and furnace applications.
✅ Correct answer

C. Photoelectric Pyrometer
Uses photoelectric sensors to detect emitted radiation.

Also non-contact and suitable for high temperatures, but the term is less commonly used in basic classifications.
❌ Less standard terminology in general usage.

D. None of these
Incorrect, because B is valid.

✅ Final Answer: B. Optical

it could be an optical pyrometer.. please correct it..
option-B