Laboratory Equipment Operation & Maintenance Flashcards

What is the correct procedure when a centrifuge becomes unbalanced during operation?

Answer: Stop the centrifuge immediately and rebalance the tubes

An unbalanced centrifuge must be stopped immediately to prevent mechanical damage and potential injury from vibration or rotor failure.

Which maintenance task should be performed on a microscope's objective lenses after each use?

Answer: Clean with lens paper and approved lens cleaner

Lens paper with approved cleaner prevents scratching the optical glass while removing oil and debris from objective lenses.

A laboratory refrigerator storing reagents reads 12°C instead of the required 2–8°C. What is the first action?

Answer: Adjust the thermostat and document the temperature excursion

The thermostat should be adjusted and the excursion documented so that reagent integrity can be assessed per laboratory protocol.

What is the purpose of running a blank when using a spectrophotometer?

Answer: To zero the instrument against the solvent baseline

A blank containing all reagents except the analyte zeroes the instrument so absorbance readings reflect only the substance being measured.

When calibrating an analytical balance, which of the following is critical?

Answer: External certified calibration weights must be used on a level, vibration-free surface

Certified weights on a level, stable surface ensure the balance reads accurately across its full measurement range.

Which of the following describes proper autoclave loading to ensure effective sterilization?

Answer: Leave space between items to allow steam penetration

Steam must contact all surfaces, so items must be spaced to allow full penetration throughout the load.

How should a pipette calibration be verified after maintenance?

Answer: Perform gravimetric testing by weighing dispensed distilled water

Gravimetric testing using distilled water's known density is the standard method for verifying pipette volume accuracy.