V

• V-Path - In angle beam tests of plate or cylindrical sections, the path of the ultrasonic beam in the test object from point of entry on the front surface to the back surface and reflecting to the front surface again. See also skip distance.
• Valence Shell - The outer electron ring of any atom.
• Van de Graaf generator - an electrostatic type x-ray generator in the million and multimillion volt category.
• Vector - A quantity having amplitude (magnitude) and direction. Normally represented as a line whose length represents the quantity’s magnitude and the angular position the phase (relative to some reference).
• Vector field - See resultant.
• Velocity - Directional distance traveled per unit time.
• Vertical Limit - The readable level of vertical indication on an A-scan.
• Vertical Linearity - See linearity, amplitude.
• Vibration - A rapid back and forth motion of a particle or solid.
• Vibrational Motion - Moving backward and forward, like a pendulum.
• Video Presentation - A cathode ray tube presentation in which radiofrequency signals have been rectified and usually filtered.
• Virgin curve - The original magnetizing curve of a material.
• Viscosity - Resistance to flow of a liquid.
• Visible dye penetrant - An intensely colored (usually red) highly penetrating liquid which will provide maximum contrast with the white developer when used for detection of surface discontinuities.
• Visual Acuity - The space visible to an eye in a given position of gaze.
• Volt (V) - (1) The unit of electromotive force or potential difference that will cause a current of one ampere to flow through a conductor whose resistance is one ohm. (2) The unit of electromotive force or potential difference between two points when one joule of energy is used to move one coulomb of charge from one point to the other.
• Voltage - Electromotive force or difference in electrical potential. Expressed in volts.
• Voltmeter - The instrument used to measure voltage.