Surface immersion calibration applies to which equipment?

• A. Incubators and ovens
• B. Refrigerators and freezers
• C. Waterbaths and heat blocks
• D. Spectrophotometers

Answer: (A)

Surface immersion calibration is about confirming the temperature at the actual surface where samples come into contact in heated equipment. Incubators and ovens deliver heat mainly through their inner surfaces and nearby air, so checking the surface temperature with a calibrated probe ensures the displayed temperature matches what the samples experience. This makes it the best fit for those devices.

Refrigerators and freezers focus on cabin air temperature, not surface heat delivery. Water baths and heat blocks rely on immersion in liquid or direct contact with a solid block, so their calibration centers on the medium in contact with the sensor rather than a surface-temperature reading. Spectrophotometers involve optical calibration rather than temperature surface calibration.