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• Occupational Dose - Includes exposure of an individual to radiation (1) in a restricted area; or (2) in the course of employment in which the individual's duties involve exposure to radiation; provided, the "occupational dose" shall not be deemed to include any exposure of an individual to radiation for the purpose of medical diagnosis or medical therapy of such individual.
• Ohms - The unit used to measure resistance in electrical systems.
• Ohm's Law - Electromotive force across a circuit is equal to the current flowing through the circuit multiplied by the total impedance of the circuit.
• Operating Point - Point on the impedance diagram that specifies the normalized inductive reactance and resistance of a coil.
• Optimum Frequency - The frequency that provides the highest signal-to-noise ratio compatible with the detection of a specific discontinuity. Each combination of discontinuity type and material may have a different optimum frequency.
• Orientation - The angular relationship of a surface, plane, discontinuity or axis to a reference plane or surface.
• Oscillatory Motions - Moving backward and forward like a pendulum.
• Oscilloscope - A device that displays how a voltage or current signal varies over time.